November 15th, 2013, 08:51 PM
CStatic control flicker only when running with Windows Classic theme
I'm dealing with a very weird visual bug. Let me explain.
I have a C++/MFC application that displays a count in a window:
The count (text) is displayed via a `CStatic` control. The mechanism is very simple. I call it every 1000 ms and update the text as such:
What happens is that the `CStatic` control updates without any issues on the OS with visual themes enabled, but if I run it on the OS with the Windows Classic theme (for instance, the screenshot above is from Windows 7) the `CStatic` control produces a visible flicker every time it updates the text.
void CTestCountdownFlickerDlg::RedrawCounter(LPCTSTR pText)
CStatic* pTxtBox = (CStatic*)this->GetDlgItem(IDC_STATIC_COUNTER);
//Get previous text
//Update only if different
if(strPrevText.Compare(pText) != 0)
//Set next text
Well, I understand that I'm nitpicking here, still I would really like to get rid of this flicker.
Here's what I tried:
1. In my actual project I tried subclassing the `CStatic` control and removed the processing of `WM_ERASEBACKGROUND` by simply returning 1. That didn't help.
2. In the same subclass for `CStatic` control I tried to override `WM_PAINT`, but that didn't work at all. So I'm not sure if I'm going too far with it at this point.
I'm attaching the C++/MFC source code for my test project I made the screenshot above for.
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