color picker behaviour changed

since...

commit db42098d
Date:   Fri Feb 9 10:47:48 2018 +0200

    use VirtualDevice in ColorFieldControl

    as part of moving use of BitmapWriteAccess inside of vcl/

changing the radiobutton selected used to change the
contents of the color picker widget, after that point it
got locked to the original contents.

Change-Id: I94c730f1868efc388cba7720364bc04a666d4fbd
Reviewed-on: https://gerrit.libreoffice.org/50969Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

cui/source/dialogs/colorpicker.cxx

@@ -265,16 +265,17 @@ void ColorFieldControl::UpdateBitmap()
 {
     const Size aSize(GetOutputSizePixel());
 
+    if (mxBitmap && mxBitmap->GetOutputSizePixel() != aSize)
+        mxBitmap.disposeAndClear();
+
     const sal_Int32 nWidth = aSize.Width();
     const sal_Int32 nHeight = aSize.Height();
 
     if (nWidth == 0 || nHeight == 0)
         return;
 
-    if (mxBitmap && mxBitmap->GetOutputSizePixel() == aSize)
-        return;
-
-    mxBitmap.disposeAndClear();
+    if (!mxBitmap)
+    {
         mxBitmap = VclPtr<VirtualDevice>::Create();
         mxBitmap->SetOutputSizePixel(aSize);
 
@@ -299,7 +300,6 @@ void ColorFieldControl::UpdateBitmap()
         pRGB = maRGB_Vert.data();
         pPercent = maPercent_Vert.data();
 
-    {
         sal_Int32 y = nHeight;
         while (y--)
         {