A while back, I too had noticed that the CHS Quick Paste menu had become very wide, but, since it didn't bother me, I ignored it. However, after today fiddling around with the settings - for example, as has been done by @Werizon in this thread - I find that though I can cause the width (string length) of the text displayed to reduce by quite a bit, the width of the QP menu stubbornly doesn't reduce all that much, staying relatively wide and leaving lots of "white space" on the RHS of the menu.