Fix calendar chart color issue (#4739)

src/Charts/CalendarWindow.cpp

@@ -161,6 +161,14 @@ CalendarWindow::CalendarWindow(Context *context)
     });
 }
 
+void
+CalendarWindow::showEvent(QShowEvent*)
+{
+    // When the chart is added to the Perspective's QStackedWidget, the Perspective's style sheets
+    // can conflict with the local calendar palette settings causing the appearance to be lost.
+    // Therefore re-apply the palette upon showEvent to ensure correct calendar appearance.
+    PaletteApplier::setPaletteRecursively(this, palette, true);
+}
 
 int
 CalendarWindow::getDefaultView
@@ -467,7 +475,6 @@ CalendarWindow::configChanged
             inactiveText = GCColor::inactiveColor(activeText, 2.5);
         }
 
-        QPalette palette;
         palette.setColor(QPalette::Active, QPalette::Window, activeWindow);
         palette.setColor(QPalette::Active, QPalette::WindowText, activeText);
         palette.setColor(QPalette::Active, QPalette::Base, activeBase);

src/Charts/CalendarWindow.h

@@ -93,10 +93,15 @@ class CalendarWindow : public GcChartWindow
         void setSummaryMetrics(const QStringList &summaryMetrics);
         void configChanged(qint32);
 
+    protected:
+
+        void showEvent(QShowEvent*) override;
+
     private:
         Context *context;
         bool first = true;
 
+        QPalette palette;
         QComboBox *defaultViewCombo;
         QComboBox *firstDayOfWeekCombo;
         QSpinBox *startHourSpin;