optimize dimmer for cursor finder

[luxferre]

Description of the new feature / enhancement

i've noticed screen dimming is resource heavy task, it is about 10 fps on pci x1 mode

Scenario when this would be used?

on laptops and lowend pc

Supporting information

No response

[ReginaldTang]

you can change the transparency in the background colour editor (see the % opacity)

[luxferre]

@ReginaldTang, transparency has nothing to do with perfomance. May be unless the overlay is fully opaque, which is unwanted.