Dialog and Menu Background color transparency

[micheus]

I checked the code and it is ready for use transparency in accord with dgud already said and tkbd shown in the pictures. It really seems to be a Windows issue.
In the wxWidgets library documentation we can find some notes related to transparency in which they say only Linux and OSX can handle it:

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Under wxGTK and wxOSX, you can use wxBG_STYLE_TRANSPARENT to obtain full transparency of the window background. Note that wxGTK supports this only since GTK 2.12 with a compositing manager enabled, call IsTransparentBackgroundSupported() to check whether this is the case
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