Resolves: tdf#92082 crash on closing color bar after redocking it

Change-Id: I015306a37abeaef17830ceab0f39cb2f3a98155c
(cherry picked from commit 14aa5c58)

svx/source/tbxctrls/colrctrl.cxx

@@ -492,14 +492,15 @@ void SvxColorDockingWindow::Resize()
     SfxDockingWindow::Resize();
 }
 
-
-
 void SvxColorDockingWindow::GetFocus()
 {
     SfxDockingWindow::GetFocus();
-    // Grab the focus to the color value set so that it can be controlled
-    // with the keyboard.
-    aColorSet->GrabFocus();
+    if (aColorSet)
+    {
+        // Grab the focus to the color value set so that it can be controlled
+        // with the keyboard.
+        aColorSet->GrabFocus();
+    }
 }
 
 bool SvxColorDockingWindow::Notify( NotifyEvent& rNEvt )