When you select a section of tect to copy or cut for pasting etc, the highlited color is black. Also the text is black, so you can't see what you are selecting. The highlited/selected color should be changed to blue or something, just not black.
Yes, I've found there's a difference. When highlighting text in a post it works like what I showed you, but when doing it in a textbox it looks the way you've seen it.
I expect that can be changed, have to find out what controls that.