Behodar:
OK, how's this for brain dead design?
"Allow only specified files" is turned off, so you'd expect that all file types are allowed. Now, let's turn it on:
Yep, that's totally brain dead alright, and it's a pet peeve of mine. The convention is that the description of the "on/off" button shouldn't change when you interact with the button. The only thing that changes should be the ON/OFF state.
If you want different descriptions - use radio buttons so the user is clear which option is being selected.





