[Windows] Fixed first moment black background of new tab.

src/lib/app/qupzilla.cpp

@@ -836,8 +836,7 @@ void QupZilla::loadSettings()
         m_usingTransparentBackground = true;
 
         QtWin::enableBlurBehindWindow(m_tabWidget->getTabBar(), true);
-        applyBlurToMainWindow();
-        update();
+        QtWin::extendFrameIntoClientArea(this);
 
         //install event filter
         menuBar()->installEventFilter(this);
@@ -909,6 +908,11 @@ void QupZilla::popupToolbarsMenu(const QPoint &pos)
     aboutToHideViewMenu();
 }
 
+bool QupZilla::isTransparentBackgroundAllowed()
+{
+    return m_usingTransparentBackground && !isFullScreen();
+}
+
 void QupZilla::setWindowTitle(const QString &t)
 {
     QString title = t;
@@ -1561,7 +1565,6 @@ SideBar* QupZilla::addSideBar()
 
 #ifdef Q_OS_WIN
     if (QtWin::isCompositionEnabled()) {
-        applyBlurToMainWindow();
         m_sideBar.data()->installEventFilter(this);
     }
 #endif
@@ -1657,6 +1660,13 @@ void QupZilla::triggerTabsOnTop(bool enable)
     Settings settings;
     settings.setValue("Browser-Tabs-Settings/TabsOnTop", enable);
     qzSettings->tabsOnTop = enable;
+
+#ifdef Q_OS_WIN
+    // workaround for changing TabsOnTop state when sidebar is visible
+    // TODO: we need a solution that changing TabsOnTop state
+    //       doesn't call applyBlurToMainWindow() from eventFilter()
+    QTimer::singleShot(0, this, SLOT(applyBlurToMainWindow()));
+#endif
 }
 
 void QupZilla::refreshHistory()
@@ -2459,11 +2469,11 @@ void QupZilla::paintEvent(QPaintEvent* event)
 
 void QupZilla::applyBlurToMainWindow(bool force)
 {
-    if (isClosing()) {
+    if (isClosing() || m_isStarting) {
         return;
     }
 
-    if (!force && (m_actionShowFullScreen->isChecked() || !m_usingTransparentBackground)) {
+    if (!force && !isTransparentBackgroundAllowed()) {
         return;
     }
     int topMargin = 0;

src/lib/app/qupzilla.h

@@ -111,6 +111,8 @@ public:
     bool isClosing() { return m_isClosing; }
     QUrl homepageUrl() { return m_homepage; }
 
+    bool isTransparentBackgroundAllowed();
+
 signals:
     void startingCompleted();
     void message(Qz::AppMessageType mes, bool state);

src/lib/webview/tabwidget.cpp

@@ -31,7 +31,9 @@
 #include "websearchbar.h"
 #include "settings.h"
 #include "qzsettings.h"
+#include "qtwin.h"
 
+#include <QTimer>
 #include <QMovie>
 #include <QMenu>
 #include <QMimeData>
@@ -282,6 +284,11 @@ int TabWidget::addView(const QUrl &url, const QString &title, const Qz::NewTabPo
 
 int TabWidget::addView(QNetworkRequest req, const QString &title, const Qz::NewTabPositionFlags &openFlags, bool selectLine, int position)
 {
+#ifdef Q_OS_WIN
+    if (p_QupZilla->isTransparentBackgroundAllowed()) {
+        QtWin::extendFrameIntoClientArea(p_QupZilla);
+    }
+#endif
     QUrl url = req.url();
     m_lastTabIndex = currentIndex();
 
@@ -358,6 +365,9 @@ int TabWidget::addView(QNetworkRequest req, const QString &title, const Qz::NewT
         }
     }
 
+#ifdef Q_OS_WIN
+    QTimer::singleShot(0, p_QupZilla, SLOT(applyBlurToMainWindow()));
+#endif
     return index;
 }