Question

I have upgraded to Delphi XE from 2009 and am experiencing a strange issue.

I create a new project, put down a TRibbon control, compile and run. Keeping the form in its default size I then minimize and restore without issues. I then maximise the form, minimize and restore and the form colour is changed to black.

I have no random code to change it and am using all defaults Delphi XE comes with and it does it each and every time without fail.

I have moved the compiled exe to a friends computer and the problem remains so I know it’s not my computer. If I turn off Aero effects the problem goes away, but put Aero back on and the problem returns.

Any ideas at all? I’m having trouble finding any relevant threads regarding this issue across the interwebs.

Thanks,
Seb

Edit (as requested, the DFM for the Form that displays this behaviour. Note: This happens on any project I start):

object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 555
  ClientWidth = 989
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  Position = poScreenCenter
  PrintScale = poNone
  Scaled = False
  PixelsPerInch = 96
  TextHeight = 13
  object Ribbon1: TRibbon
    Left = 0
    Top = 0
    Width = 989
    Height = 143
    Caption = 'Ribbon1'
    ExplicitLeft = 104
    ExplicitTop = 296
    ExplicitWidth = 0
    StyleName = 'Ribbon - Luna'
  end
end

Nothing fanciful at all, it’s just a new project with a single form.

Answer 1

I am able to reproduce the bug, here are some of the issues I discovered. Maybe they’ll help someone figure this thing out.

• If I place a button on the form and call Invalidate from the button’s OnClick event, the form gets it’s colors back.
• If I place a place a timer on the form, enable the timer from WndProc on WM_SIZE with wParam = SIZE_MAXIMIZED, then call Invalidate from the timer the form gets it’s colors back. This is essentially the same as the first method (calling Invalidate from a button), but the timer makes this automatic and ensures Invalidate is called only when there are no more messages to be processed. I tried the same with a simple PostMessage but didn’t work (ie: I was probably Invalidate-ing too soon, and that’s probably an other clue)
• Interesting: If I make Application.MainFormOnTaskbar := False in the project’s source, I no longer see the black form.

Workaround

The ribbon takes up the top part of the form. Place a TPanel on the rest of the form, make it Align = alClient and put everything on the Panel. The Black behind the panel is no longer visible!