diff --git a/lcl/interfaces/qt/qtobjects.pas b/lcl/interfaces/qt/qtobjects.pas
index f65e53f60e..5469a19e75 100644
--- a/lcl/interfaces/qt/qtobjects.pas
+++ b/lcl/interfaces/qt/qtobjects.pas
@@ -779,7 +779,7 @@ type
     destructor Destroy; override;
     procedure ReloadPaletteBegin; // used in QEventPaletteChange !
     procedure ReloadPaletteEnd; // used in QEventPaletteChange !
-    procedure setColor(const AColor: PQColor); overload;
+    procedure setColor(const AColor: PQColor);
     procedure setTextColor(const AColor: PQColor);
     property Handle: QPaletteH read FHandle;
     property CurrentColor: TQColor read FCurrentColor;
diff --git a/lcl/interfaces/qt/qtwinapi.inc b/lcl/interfaces/qt/qtwinapi.inc
index deae74ab25..17abb2b9b6 100644
--- a/lcl/interfaces/qt/qtwinapi.inc
+++ b/lcl/interfaces/qt/qtwinapi.inc
@@ -2412,7 +2412,14 @@ begin
   begin
     AWidget := HwndFromWidgetH(QtDC.Parent);
     if (AWidget <> 0) and Assigned(TQtWidget(AWidget).LCLObject) then
+    begin
       ATransparent := not (csOpaque in TQtWidget(AWidget).LCLObject.ControlStyle);
+      // issue #26607
+      if ATransparent and (TQtWidget(AWidget).LCLObject is TCustomPanel) and
+        (TQtWidget(AWidget).LCLObject.Color <> clDefault) and
+        not TCustomPanel(TQtWidget(AWidget).LCLObject).ParentColor then
+          ATransparent := False;
+    end;
   end;
 
   case Style of