Diagnosing iCloud problems using brctl, sync budgets and throttles
How much help does macOS provide for the diagnosis of iCloud problems? What does iCloud ‘throttle’, and what are its ‘budgets’?
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.