Cannot drag to select layers in timeline

[ploxyzero]

I'm encountering the most unusual and frustrating issue ever. For whatever reason, I cannot drag-to-select any layer in the timeline. I've gone as far as completely uninstalling the entire Creative Cloud suite with Adobe's cleaning tool, but still having the same issue even after re-installing After Effects. 

I have no idea how to fix this or what even caused this issue to start happening in the first place.

[Mylenium]

I think there's a known issue/ bug with this. Outside that the usual steps apply: Check your hardware acceleration settings, update your graphics drivers and in this caser also your mouse/ tablet driver. Hyper-sensitive gaming mice for instance can cause lots of indadvertend unregistered clicks and may need to be toned down for professional apps. Same with wacky tablet registration and such. No guarantees that any of that will fix it, though.

Mylenium