How to fix problems with iCloud and iCloud Drive
When should you turn iCloud off to try to solve syncing problems? What use is a Content Caching server? What tools can help diagnose and fix problems?
brctl
Fix:
Preferences → Tools → Spring-loaded Tool Shortcuts
«[…] change the Timing Sensitivity from 200 to 675 miliseconds and you should be good to go.»
That is called spring-loaded tool, it allows you to temporarily switch to a given tool, use it, and return to the previous tool. For instance: you use the brush tool, then hold Z, click to zoom, release the Z key and you get the Brush tool you had before. You need to click quickly to switch tool permanently.