If you read through the threads here and at SketchUcation you will find countless instances of a ‘non-administrator’ [aka double-click ‘Run’] installation causing very weird issues.
No one is forcing you to do it properly. 
After all you might be blessed, or have your overly-complex Windows-users permissions set ‘just-right’…
But many don’t and do get weirdness.
Perhaps this Tag-name-edit problem relates to something else entirely, but installing SketchUp from its exe properly will never hurt…
If you already installed it ‘wrong’ then a reinstall of the installer’s exe, using the >right-click>context-menu>Run as administrator… the choosing Repair will reset thing without uninstalling or messing you any earlier personalization…