Typo fixed.
In fact, the inconsistency resides in many English speaking people's abuse of capitalized words... Capitalized words should be reserved for the first word in a phrase (and not either for the first word after a colon or a semi-colon), for proper names, and (by extent and abuse) to emphasize a specific word in a phrase. Since I was the one adding those tabs, I used proper capitalization in their name... For consistency, the true solution would be to remove all the abusive "captitalizations" in the viewer UI, but I'm afraid I have no time to waste doing so (if someone with a proper grasp of grammar, spelling and typographic rules volunteers for such a task, I'll gladly use their work and credit them)...
Done but untested (I always left the UI scale at 1.000 and never needed to change it when changing my monitors and screen resolution).
As it implies, it allows for a screen-resolution independent UI (especially fonts) scale. It works just fine under Linux (not sure about Windows and MacOS-X), provided your driver is properly configured (or could read the EDID information from the monitor): the critical info for this feature to work is the screen DPI resolution.