Doesn't work - can't see the current size of my window anywhere, nor do a I see any way to add it to my toolbar etc.

No option to change the position of the little popup with the viewport size...
This is a problem when you are developing with WordPress..

Not working in latest dev edition! And btw: why only show it on resize and not just always???

Doesn't do anything, not showing size or anything at all. This garbage should be removed from Add-ons

WHERE does show this Add-on the current view port size?

This addon is a real joke, nothing happen.

Nothing happens after install (FF57 on Mac), so it doesn't seem to work. A pity, because an add-on like this would be really helpful.

When installing it, doesn't seems to do anything..