Change default bg_col of ImageButton()

[ApoorvaJ]

For ImageButton(), I think the default value of bg_col should be (0,0,0,0) instead of (0,0,0,1).

Most of the time, an ImageButton will be used to create buttons with icons on them. The default value makes it seem like a bug - that the code is ignoring the alpha.

Here's a screenshot of the default behavior of an Image() vs the default behavior of an ImageButton():

[ApoorvaJ]

Related issue:
When using ImageButton(), if frame_padding is set to 0, and the bg_col alpha is 0, then the button isn't drawn at all.

Makes sense when the image is fully opaque, but otherwise the button should be drawn behind the image, even if padding is 0.

[ocornut]

Agreeing for first change. Fixed both. Thanks!

[ApoorvaJ]

That was quick. Thanks! :)