C＃-悬停按钮可删除透明背景

Question

I'm developing an application which has several buttons with a transparent background. One of these is a custom exit button, rather than using the standard windows border. This exit button has two colors, the other which is shown using the MouseEnter event. The exit button is a cross with a transparent background.

The transparent background works fine, until you hover the button. Then the backcolor somehow appears to change to Control and the transparency is lost. Once you move the cursor away from the button it's back to normal. The weird thing here is that the exact same button with the exact same code works on several other windows except this one, which is the main form.

I tried removing all Mouseevents and click events and only have a button with a transparent background. Now, even without any MouseEnter event and without any change of the button background image, the transparency is lost once you hover the button. So basically this is a static button with no function at all which still reacts once you hover it by changing the BackColor, why?

I have a vague memory of experiencing this issue before but I just can't seem to figure out what I did to solve it.

Thanks in advance, Fredrik

Answer 1

I have now found the issue. If anyone else is experiencing this issue, make sure to set your MouseDownBackColor and MouseOverBackColor to Transparent in the FlatAppearance section. That did the trick.