Hi there!
I have an idea - there should be a context menu (in RMB click menu) entry, that would invert the current selection.
As an example, imagine following string in - let's say - search bar on any page:
"nothing seems to be more important"
When any part of this sentence is selected - let's assume the word "more" is selected (highlighted) - then this 'invert selection' function, would cause de-selection of currently selected part and selection of all the others characters in such a string - so after using, it would change the selection to "nothing seems to be important" string, excluding previously selected word "more".
Please think about it.
Best regards,
FixxxeR