Make Dimension Driven?
The highlighted dimension has made the sketch over defined or unsolvable.
Either click Cancel to abandon
the operation (the dimension is not placed), or select one of the following
options, then click OK:
Make This Dimension
Driven (The over defined or unsolvable state is repaired.)
Leave
This Dimension Driving (The sketch remains over defined or unsolvable.
Look for other dimensions or relations that you can delete or change.)
Select Don't
ask again to suppress this dialog box. The option you last used
will apply by default.
Use the right-click menu Driven
option to toggle between dimension driven and dimension driving.