A Different Kind Of Flicker.

I have just run into an issue of screen flicker that I haven't been able to solve. I have a panel with dozens of controls on it. Painted onto the panel, behind the controls, are a few colored rectangles.

Those rectangles flicker whenever the mouse is moved over any control, or off the panel. Basically, a paint event for the panel is raised whenever the mouse leaves the panel.

Therefore, I thought that if I only painted the rectangles when they needed to be painted, not every time the Paint event was raised, that I would be able to avoid the flicker. After all, there is no obvious reason why they would need to be re-painted just because the mouse moved over a control on the panel.

the paint event was still being raised, and the panel just wasn't painting the rectangles, so they weren't being drawn at all (but they sure didn't flicker). So, the flicker is being caused by the fact that the paint event clears the panel, which gets displayed in a cleared state for a fraction of a second, then the rectangles are drawn in.

Doublebuffering the form has no discernible impact, which may well be because the screen draws the absence of the rectangles on one frame, then draws the presence of the rectangles on the next frame. They both get shown in sequence, so the rectangles appear to flicker badly.

One obvious alternative is to not even draw the rectangles, which works great, and they are only useful visual guides, not essential components. Still, that doesn't seem like a good solution.

So what I am looking for is a way to supress the display of the undrawn image before showing the finished image.