Less on 2 symbols

We don't support Opera 12, and Firefox's property was the unprefixed one.

* Fix getSelectorFromElement when # is a selector

* Thanks to @vanduynslagerp remove regex to validate selector

* Fix #17964

Some browsers are lazy when updating dom elements after transition effects. This can be fixed by reading element properties such as offsetHeight or offsetWidth. However, creating a function using the Function constructor just to access such element, results in a violation of Content Security Policy (where applied), which in turn crashes the application. This fix actually reverts to the way this was handled in v3 and should work as intended.

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Mostly KeyboardEvent.which and MouseEvent.which values.

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