I'm wondering how not to move it everytime I click something on the main screen

Options > Preferences > Theme Editor Edit Cursor Edit Cursor (Alternate) Play Cursor Click on the color box next to the above choices. I have a black background, and light colored media items. Black works greatfor that, but colors look like Caca..

Thanks Mercado :)

delayed when clicking on the ruler 

Oh, yes! Thank you, Mercado_Negro!