Polygon Tool doesn't get Focus

when the polygon tool is initially activated, the measurements toolbar doesn’t accept the input of the number of sides similar to the circle tool.

clicking on the title bar fixes the issue, therefore probably caused by a missing focus on the measurement toolbar?

SUP: rev 15.3.331 x64
OS: W7 Pro x64

For me they seem to work the same way.
Select the tool > ‘Measurements’ box shows sides … accepts changes > type 7 (or whatever, without s) and hit [Enter] > cursor changes accordingly to 7 sides and the ‘Measurements’ box shows sides 7.

seems to be erratic and not limited to the polygon tool only but affects all tools with a sides input.