Lag/Delay issues with tool swaps & other tool (marquee, lasso, brush) issues/bugs.

It's been a common issue for me since years back. I've been burnt out and had no willpower to start projects even if I'd get a stroke of genius idea (I have still been paying). Anyways. I'm back now and doing some hobby projects to get back into the groove. This is, however, very hard when the application takes time to swap between tools for an example.

Brush Tool:

I can draw fine, there's no lag. But whenever I try to swap to another tool it takes literally forever and sometimes I've used the 'alt + tab' and that would have "fixed" the problem.

Rectangular Marquee Tool:

(This issue ALSO includes Lasso Tool and the Brush tool.)

Sometimes when I swap to this tool it starts to act up badly and in the end I'll have to restart the application to make it go away. If this happens, I'm not allowed to use my brush either - it just draws blank (this part is however not included in the video as I tried it the next time this issue showed itself). Look at the included handheld video footage.

Other times when I'm using the wacom pen to click on 'create new layer' or some of the other functions on the bottom of the "layers box", such as "add layer mask" become greyed. Like I would have pressed it but not released the mouse button. Just freezing like this, unable to press them. (Keyboard shortcut, however works, but is annoying to do because it creates a dialogue.) Have had to stop my workflow and restart the app and kill the mood this way several times already.

EDIT: I have installed the latest update. I'll keep you updated if this greyed out thing still occurs.

Computer specs:

Windows 10

Intel i7 6850K

EVGA Geforce GTX1080Ti Founders Ed.

32GB Ram

Other

Wacom Intous 4 (PTK-640)

I have been known as a man of great patience! But it's been years and the same thing perstists and furthermore, new issues arise.