This issue always existed since the Grid Desktop was implemented, but I thought it would be quickly found and fixed. Since it still happens in 4.8.5 (and after several years) I'm reporting it.

Widgets on the Grid Desktop cause two panels (settings / resize / rotate / remove icon bars) to pop up to the side when hovering the mouse over them. Depending on how you move the mouse, either each bar will pop up on a different side or both will appear in the same spot one over the other. One of those bars disappears soon after taking the mouse off the widget, while the other sticks around for longer. One bar has the full set of icons, while the additional one has only the "settings" and "close" icons. When the extra overlaps the normal one, it's impossible to click any of the icons on it.

Reproducible: Always

Steps to Reproduce:
1. Set the desktop type / layout to Grid Desktop.
2. Add at least one widget to the desktop (Analog Clock works).
3. Hover the mouse over it until the bar with configuration icons pops up to its side.
Actual Results:  
As you hold the mouse over the widget, two bars will appear instead of one, usually overlapping each other and making themselves unusable.

Expected Results:  
Only one bar should appear as you hover your mouse over the widget, like the other desktop layouts.

This doesn't happen with the normal Desktop layout, the Folder View layout or other desktops... it's an issue with the Grid Desktop. It still happens with a fresh configuration (.kde & .kde4 folders) and I remember the theme doesn't make any difference either (it happens with the official Air theme too). Image showing the problem here: http://i48.tinypic.com/j10o48.png