The Problem: The task manager dropdown menus are all transparent and not readable at all. The same goes for all the dropdown menus of libre office. I have tried to change the desktop theme but the transparency kept on appearing on all those menus hindering me from reading them. Disabling all the effects of the desktop (ALT + Shift + F12) did not help at all as well.
Objective: I need to remove all the opacity and transparency of those menus. I simply need a clear readable desktop environment.
Any suggestions, comments or solutions will be greatly appreciated.
Note: I am using Kubuntu 15.10 (Not a fresh installation. I have just installed the KDE desktop environment on top of the Ubuntu Mate 15.10 then decided to use it as my default.