diff --git a/src/qt/bitcoingui.cpp b/src/qt/bitcoingui.cpp
index 5cac479420..0418d9f88f 100644
--- a/src/qt/bitcoingui.cpp
+++ b/src/qt/bitcoingui.cpp
@@ -125,8 +125,7 @@ BitcoinGUI::BitcoinGUI(const PlatformStyle *_platformStyle, const NetworkStyle *
     spinnerFrame(0),
     platformStyle(_platformStyle)
 {
-    /* Open CSS when configured */
-    this->setStyleSheet(GUIUtil::loadStyleSheet());
+    GUIUtil::loadStyleSheet(this);
 
     QSettings settings;
     if (!restoreGeometry(settings.value("MainWindowGeometry").toByteArray())) {
@@ -151,7 +150,7 @@ BitcoinGUI::BitcoinGUI(const PlatformStyle *_platformStyle, const NetworkStyle *
     setWindowIcon(networkStyle->getTrayAndWindowIcon());
     setWindowTitle(windowTitle);
 
-    rpcConsole = new RPCConsole(_platformStyle, 0);
+    rpcConsole = new RPCConsole(_platformStyle, this);
     helpMessageDialog = new HelpMessageDialog(this, HelpMessageDialog::cmdline);
 #ifdef ENABLE_WALLET
     if(enableWallet)
@@ -1530,8 +1529,7 @@ void BitcoinGUI::showProgress(const QString &title, int nProgress)
 {
     if (nProgress == 0)
     {
-        progressDialog = new QProgressDialog(title, "", 0, 100);
-        progressDialog->setStyleSheet(GUIUtil::loadStyleSheet());
+        progressDialog = new QProgressDialog(title, "", 0, 100, this);
         progressDialog->setWindowModality(Qt::ApplicationModal);
         progressDialog->setMinimumDuration(0);
         progressDialog->setCancelButton(0);
diff --git a/src/qt/coincontroldialog.cpp b/src/qt/coincontroldialog.cpp
index 3f3f4c6e67..0829ce7efb 100644
--- a/src/qt/coincontroldialog.cpp
+++ b/src/qt/coincontroldialog.cpp
@@ -51,9 +51,6 @@ CoinControlDialog::CoinControlDialog(const PlatformStyle *_platformStyle, QWidge
 {
     ui->setupUi(this);
 
-    /* Open CSS when configured */
-    this->setStyleSheet(GUIUtil::loadStyleSheet());
-
     GUIUtil::setFont({ui->labelCoinControlQuantityText,
                       ui->labelCoinControlBytesText,
                       ui->labelCoinControlAmountText,
@@ -237,9 +234,8 @@ void CoinControlDialog::buttonToggleLockClicked()
         CoinControlDialog::updateLabels(model, this);
     }
     else{
-        QMessageBox msgBox;
+        QMessageBox msgBox(this);
         msgBox.setObjectName("lockMessageBox");
-        msgBox.setStyleSheet(GUIUtil::loadStyleSheet());
         msgBox.setText(tr("Please switch to \"List mode\" to use this function."));
         msgBox.exec();
     }
diff --git a/src/qt/dash.cpp b/src/qt/dash.cpp
index dfcd3b8cde..1960be60c9 100644
--- a/src/qt/dash.cpp
+++ b/src/qt/dash.cpp
@@ -775,6 +775,11 @@ int main(int argc, char *argv[])
 
         GUIUtil::setStyleSheetDirectory(strCustomDir);
     }
+    // Validate -debug-ui
+    if (gArgs.GetBoolArg("-debug-ui", false)) {
+        QMessageBox::warning(0, QObject::tr(PACKAGE_NAME),
+                                "Warning: UI debug mode (-debug-ui) enabled" + QString(gArgs.IsArgSet("-custom-css-dir") ? "." : " without a custom css directory set with -custom-css-dir."));
+    }
 
     // Subscribe to global signals from core
     uiInterface.InitMessage.connect(InitMessage);
diff --git a/src/qt/guiutil.cpp b/src/qt/guiutil.cpp
index 0d190eed71..478bc7e020 100644
--- a/src/qt/guiutil.cpp
+++ b/src/qt/guiutil.cpp
@@ -55,6 +55,7 @@
 #include <QSettings>
 #include <QTextDocument> // for Qt::mightBeRichText
 #include <QThread>
+#include <QTimer>
 #include <QUrlQuery>
 #include <QMouseEvent>
 
@@ -80,6 +81,7 @@ void ForceActivation();
 
 namespace GUIUtil {
 
+static CCriticalSection cs_css;
 // The default stylesheet directory
 static const QString defaultStylesheetDirectory = ":css";
 // The actual stylesheet directory
@@ -1023,43 +1025,92 @@ const std::vector<QString> listThemes()
     return vecThemes;
 }
 
-// Open CSS when configured
-QString loadStyleSheet()
+void loadStyleSheet(QWidget* widget, bool fDebugWidget)
 {
+    AssertLockNotHeld(cs_css);
+    LOCK(cs_css);
+
     static std::unique_ptr<QString> stylesheet;
+    static std::set<QWidget*> setWidgets;
 
-    if (stylesheet == nullptr) {
-        stylesheet = std::make_unique<QString>();
+    bool fDebugCustomStyleSheets = gArgs.GetBoolArg("-debug-ui", false) && isStyleSheetDirectoryCustom();
+    bool fStyleSheetChanged = false;
 
-        QSettings settings;
-        QDir themes(":css");
-        QString theme = settings.value("theme", "").toString();
+    if (stylesheet == nullptr || fDebugCustomStyleSheets) {
+        auto hasModified = [](const std::vector<QString>& vecFiles) -> bool {
+            static std::map<const QString, QDateTime> mapLastModified;
 
-        // Make sure settings are pointing to an existent theme
-        if (!isStyleSheetDirectoryCustom() && (theme.isEmpty() || !themes.exists(theme))) {
-            theme = defaultTheme;
-            settings.setValue("theme", theme);
-        }
-
-        auto loadFile = [&](const QString& name) {
-            QFile qFile(stylesheetDirectory + "/" + name + (isStyleSheetDirectoryCustom() ? ".css" : ""));
-            if (qFile.open(QFile::ReadOnly)) {
-                stylesheet->append(QLatin1String(qFile.readAll()));
+            bool fModified = false;
+            for (auto file = vecFiles.begin(); file != vecFiles.end() && !fModified; ++file) {
+                QFileInfo info(*file);
+                QDateTime lastModified = info.lastModified(), prevLastModified;
+                auto it = mapLastModified.emplace(std::make_pair(*file, lastModified));
+                prevLastModified = it.second ? QDateTime() : it.first->second;
+                it.first->second = lastModified;
+                fModified = prevLastModified != lastModified;
             }
+            return fModified;
         };
 
+        auto loadFiles = [&](const std::vector<QString>& vecFiles) -> bool {
+            if (fDebugCustomStyleSheets && !hasModified(vecFiles)) {
+                return false;
+            }
+
+            stylesheet = std::make_unique<QString>();
+
+            for (const auto& file : vecFiles) {
+                QFile qFile(file);
+                if (!qFile.open(QFile::ReadOnly)) {
+                    throw std::runtime_error(strprintf("%s: Failed to open file: %s", __func__, file.toStdString()));
+                }
+                stylesheet->append(QLatin1String(qFile.readAll()));
+            }
+            return true;
+        };
+
+        auto pathToFile = [&](const QString& file) -> QString {
+            return stylesheetDirectory + "/" + file + (isStyleSheetDirectoryCustom() ? ".css" : "");
+        };
+
+        std::vector<QString> vecFiles;
         // If light/dark theme is used load general styles first
         if (dashThemeActive()) {
-            loadFile("general");
 #ifndef Q_OS_MAC
-            loadFile("scrollbars");
+            vecFiles.push_back(pathToFile("scrollbars"));
 #endif
+            vecFiles.push_back(pathToFile("general"));
         }
+        vecFiles.push_back(pathToFile(getActiveTheme()));
 
-        loadFile(theme);
+        fStyleSheetChanged = loadFiles(vecFiles);
     }
 
-    return *stylesheet;
+    bool fUpdateStyleSheet = fDebugCustomStyleSheets && fStyleSheetChanged;
+
+    if (fDebugWidget) {
+        setWidgets.insert(widget);
+        QWidgetList allWidgets = QApplication::allWidgets();
+        auto it = setWidgets.begin();
+        while (it != setWidgets.end()) {
+            if (!allWidgets.contains(*it)) {
+                it = setWidgets.erase(it);
+                continue;
+            }
+            if (fUpdateStyleSheet && *it != widget) {
+                (*it)->setStyleSheet(*stylesheet);
+            }
+            ++it;
+        }
+    }
+
+    if (widget) {
+        widget->setStyleSheet(*stylesheet);
+    }
+
+    if (!ShutdownRequested() && fDebugCustomStyleSheets) {
+        QTimer::singleShot(200, [] { loadStyleSheet(); });
+    }
 }
 
 FontFamily fontFamilyFromString(const QString& strFamily)
@@ -1431,12 +1482,15 @@ QFont getFont(FontWeight weight, bool fItalic, int nPointSize)
         font.setWeight(qWeight);
         font.setStyle(fItalic ? QFont::StyleItalic : QFont::StyleNormal);
     }
-    qDebug() << "GUIUtil::getFont() - " << font.toString() << " family: " << font.family() << ", style: " << font.styleName() << " match: " << font.exactMatch();
 
     if (nPointSize != -1) {
         font.setPointSizeF(getScaledFontSize(nPointSize));
     }
 
+    if (gArgs.GetBoolArg("-debug-ui", false)) {
+        qDebug() << __func__ << ": font size: " << font.pointSizeF() << " family: " << font.family() << ", style: " << font.styleName() << " match: " << font.exactMatch();
+    }
+
     return font;
 }
 
@@ -1450,6 +1504,12 @@ QFont getFontBold()
     return getFont(FontWeight::Bold);
 }
 
+QString getActiveTheme()
+{
+    QSettings settings;
+    return settings.value("theme", defaultTheme).toString();
+}
+
 bool dashThemeActive()
 {
     QSettings settings;
diff --git a/src/qt/guiutil.h b/src/qt/guiutil.h
index 8e261fb96f..a81ceaab08 100644
--- a/src/qt/guiutil.h
+++ b/src/qt/guiutil.h
@@ -253,8 +253,10 @@ namespace GUIUtil
     /** Return a list of all theme css files */
     const std::vector<QString> listThemes();
 
-    /** Load global CSS theme */
-    QString loadStyleSheet();
+    /** Updates the widgets stylesheet and adds it to the list of ui debug elements
+        if fDebugWidget is true. Beeing on that list means the stylesheet of the
+        widget gets updated if the related css files has been changed if -debug-ui mode is active. */
+    void loadStyleSheet(QWidget* widget = nullptr, bool fDebugWidget = true);
 
     enum class FontFamily {
         SystemDefault,
@@ -327,7 +329,10 @@ namespace GUIUtil
     /** Get the default bold QFont */
     QFont getFontBold();
 
-    /** Check if a dash specific theme is activated (light/dark) */
+    /** Return the name of the currently active theme.*/
+    QString getActiveTheme();
+
+    /** Check if a dash specific theme is activated (light/dark).*/
     bool dashThemeActive();
 
     /** Disable the OS default focus rect for macOS because we have custom focus rects
diff --git a/src/qt/masternodelist.cpp b/src/qt/masternodelist.cpp
index 8a8a880d04..4ab9a9fe05 100644
--- a/src/qt/masternodelist.cpp
+++ b/src/qt/masternodelist.cpp
@@ -79,7 +79,7 @@ MasternodeList::MasternodeList(const PlatformStyle* platformStyle, QWidget* pare
 
     QAction* copyProTxHashAction = new QAction(tr("Copy ProTx Hash"), this);
     QAction* copyCollateralOutpointAction = new QAction(tr("Copy Collateral Outpoint"), this);
-    contextMenuDIP3 = new QMenu();
+    contextMenuDIP3 = new QMenu(this);
     contextMenuDIP3->addAction(copyProTxHashAction);
     contextMenuDIP3->addAction(copyCollateralOutpointAction);
     connect(ui->tableWidgetMasternodesDIP3, SIGNAL(customContextMenuRequested(const QPoint&)), this, SLOT(showContextMenuDIP3(const QPoint&)));
diff --git a/src/qt/overviewpage.cpp b/src/qt/overviewpage.cpp
index f59ac28e7b..c44b1c998f 100644
--- a/src/qt/overviewpage.cpp
+++ b/src/qt/overviewpage.cpp
@@ -232,10 +232,11 @@ void OverviewPage::setBalance(const CAmount& balance, const CAmount& unconfirmed
     ui->labelWatchImmature->setText(BitcoinUnits::floorHtmlWithUnit(nDisplayUnit, watchImmatureBalance, false, BitcoinUnits::separatorAlways));
     ui->labelWatchTotal->setText(BitcoinUnits::floorHtmlWithUnit(nDisplayUnit, watchOnlyBalance + watchUnconfBalance + watchImmatureBalance, false, BitcoinUnits::separatorAlways));
 
-    // only show immature (newly mined) balance if it's non-zero, so as not to complicate things
+    // only show immature (newly mined) balance if it's non-zero or in UI debug mode, so as not to complicate things
     // for the non-mining users
-    bool showImmature = immatureBalance != 0;
-    bool showWatchOnlyImmature = watchImmatureBalance != 0;
+    bool fDebugUI = gArgs.GetBoolArg("-debug-ui", false);
+    bool showImmature = fDebugUI || immatureBalance != 0;
+    bool showWatchOnlyImmature = fDebugUI || watchImmatureBalance != 0;
 
     // for symmetry reasons also show immature label when the watch-only one is shown
     ui->labelImmature->setVisible(showImmature || showWatchOnlyImmature);
@@ -298,7 +299,7 @@ void OverviewPage::setWalletModel(WalletModel *model)
         connect(model, SIGNAL(balanceChanged(CAmount,CAmount,CAmount,CAmount,CAmount,CAmount,CAmount)), this, SLOT(setBalance(CAmount,CAmount,CAmount,CAmount,CAmount,CAmount,CAmount)));
 
         connect(model->getOptionsModel(), SIGNAL(displayUnitChanged(int)), this, SLOT(updateDisplayUnit()));
-        updateWatchOnlyLabels(model->haveWatchOnly());
+        updateWatchOnlyLabels(model->haveWatchOnly() || gArgs.GetBoolArg("-debug-ui", false));
         connect(model, SIGNAL(notifyWatchonlyChanged(bool)), this, SLOT(updateWatchOnlyLabels(bool)));
 
         // explicitly update PS frame and transaction list to reflect actual settings
diff --git a/src/qt/rpcconsole.cpp b/src/qt/rpcconsole.cpp
index dde7e76182..79493dab5f 100644
--- a/src/qt/rpcconsole.cpp
+++ b/src/qt/rpcconsole.cpp
@@ -450,7 +450,7 @@ void RPCExecutor::request(const QString &command)
 }
 
 RPCConsole::RPCConsole(const PlatformStyle *_platformStyle, QWidget *parent) :
-    QWidget(parent),
+    QWidget(parent, Qt::Window),
     ui(new Ui::RPCConsole),
     clientModel(0),
     historyPtr(0),
@@ -461,9 +461,6 @@ RPCConsole::RPCConsole(const PlatformStyle *_platformStyle, QWidget *parent) :
 {
     ui->setupUi(this);
 
-    /* Open CSS when configured */
-    this->setStyleSheet(GUIUtil::loadStyleSheet());
-
     GUIUtil::setFont({ui->label_9,
                       ui->labelNetwork,
                       ui->label_10,
diff --git a/src/qt/sendcoinsdialog.cpp b/src/qt/sendcoinsdialog.cpp
index 395b4bae31..d2cf188c0b 100644
--- a/src/qt/sendcoinsdialog.cpp
+++ b/src/qt/sendcoinsdialog.cpp
@@ -900,7 +900,7 @@ void SendCoinsDialog::coinControlFeatureChanged(bool checked)
 // Coin Control: button inputs -> show actual coin control dialog
 void SendCoinsDialog::coinControlButtonClicked()
 {
-    CoinControlDialog dlg(platformStyle);
+    CoinControlDialog dlg(platformStyle, this);
     dlg.setModel(model);
     dlg.exec();
     coinControlUpdateLabels();
diff --git a/src/qt/transactiondescdialog.cpp b/src/qt/transactiondescdialog.cpp
index 648d680a59..b4c0c1585e 100644
--- a/src/qt/transactiondescdialog.cpp
+++ b/src/qt/transactiondescdialog.cpp
@@ -18,8 +18,6 @@ TransactionDescDialog::TransactionDescDialog(const QModelIndex &idx, QWidget *pa
 {
     ui->setupUi(this);
     setWindowTitle(tr("Details for %1").arg(idx.data(TransactionTableModel::TxHashRole).toString()));
-    /* Open CSS when configured */
-    this->setStyleSheet(GUIUtil::loadStyleSheet());
     QString desc = idx.data(TransactionTableModel::LongDescriptionRole).toString();
     ui->detailText->setHtml(desc);
 }
diff --git a/src/qt/transactionview.cpp b/src/qt/transactionview.cpp
index 9f57d40b28..982c6a3edb 100644
--- a/src/qt/transactionview.cpp
+++ b/src/qt/transactionview.cpp
@@ -556,7 +556,7 @@ void TransactionView::showDetails()
     QModelIndexList selection = transactionView->selectionModel()->selectedRows();
     if(!selection.isEmpty())
     {
-        TransactionDescDialog *dlg = new TransactionDescDialog(selection.at(0));
+        TransactionDescDialog* dlg = new TransactionDescDialog(selection.at(0), this);
         dlg->setAttribute(Qt::WA_DeleteOnClose);
         dlg->show();
     }
diff --git a/src/qt/utilitydialog.cpp b/src/qt/utilitydialog.cpp
index 71b7f0ecef..db84c43c15 100644
--- a/src/qt/utilitydialog.cpp
+++ b/src/qt/utilitydialog.cpp
@@ -100,6 +100,7 @@ HelpMessageDialog::HelpMessageDialog(QWidget *parent, HelpMode helpMode) :
         strUsage += HelpMessageOpt("-resetguisettings", tr("Reset all settings changed in the GUI").toStdString());
         if (showDebug) {
             strUsage += HelpMessageOpt("-uiplatform", strprintf("Select platform to customize UI for (one of windows, macosx, other; default: %s)", BitcoinGUI::DEFAULT_UIPLATFORM));
+            strUsage += HelpMessageOpt("-debug-ui", "Updates the UI's stylesheets in realtime with changes made to the css files in -custom-css-dir and forces some widgets to show up which are usually only visible under certain circumstances. (default: 0)");
         }
         strUsage += HelpMessageOpt("-windowtitle=<name>", _("Sets a window title which is appended to \"Dash Core - \""));
 
@@ -210,8 +211,7 @@ ShutdownWindow::ShutdownWindow(QWidget *parent, Qt::WindowFlags f):
 {
     setObjectName("ShutdownWindow");
 
-    /* Open CSS when configured */
-    this->setStyleSheet(GUIUtil::loadStyleSheet());
+    GUIUtil::loadStyleSheet(this, false);
 
     QVBoxLayout *layout = new QVBoxLayout();
     layout->addWidget(new QLabel(
diff --git a/src/qt/walletview.cpp b/src/qt/walletview.cpp
index 16a264bb5d..7383f31a47 100644
--- a/src/qt/walletview.cpp
+++ b/src/qt/walletview.cpp
@@ -385,8 +385,7 @@ void WalletView::showProgress(const QString &title, int nProgress)
 {
     if (nProgress == 0)
     {
-        progressDialog = new QProgressDialog(title, "", 0, 100);
-        progressDialog->setStyleSheet(GUIUtil::loadStyleSheet());
+        progressDialog = new QProgressDialog(title, "", 0, 100, this);
         progressDialog->setWindowModality(Qt::ApplicationModal);
         progressDialog->setMinimumDuration(0);
         progressDialog->setCancelButton(0);