Fixing a Menu Drawing Glitch in Delphi 4

by David Yowell - yowelld@hotmail.com

You may have noticed that the images for certain disabled menu items in the Delphi 4 look like indistinguishable gray blobs as seen in the following figure.

The glitch is in the VCL so it affects both the Delphi IDE and user applications created with Delphi. However, there is an easy fix that involves changing a few lines of code in the ImgList unit. In the TCustomImageList.DoDraw method eliminate line 583:

  ImageList_DrawEx(Handle, Index, FMonoBitmap.Canvas.Handle, 0,0,0,0, 0,0,
    ILD_MASK);

  FMonoBitmap.Canvas.Brush.Color := BkColor;
  FMonoBitmap.Canvas.FillRect(Rect(0, 0, Self.Width, Self.Height));
  ImageList_DrawEx(Handle, Index, FMonoBitmap.Canvas.Handle, 0,0,0,0, 0,0,
    ILD_TRANSPARENT);

Note: Modifying the code for your Delphi 4 VCL has a few pitfalls. You may want to make sure you understand what you are doing before changing code shipped from Borland/Inprise. If you need a little hand-holding, here is the key points you need to look out for:

Instructions for modifying the VCL:

• Create a directory called [DelphiPath]\MyVCL where [DelphiPath] is the directory in which Delphi is installed.
• Add [DelphiPath]\MyVCL as the first entry in the Library Path in the Environment Options dialog box.
• Copy the source code of the unit you wish to modify to the [DelphiPath]\MyVCL  directory.
• Modify the VCL unit and recompile your application.

• Sometimes it is necessary to exit and restart Delphi before it will detect and compile your modified VCL code.
• Never modify the interface section in a VCL unit.
• In Delphi 3 & 4, your modifications will only appear at runtime since the IDE continues to make use of the standard VCL design package libraries. Also, this method will not work with runtime packages.