This happens often when using multiple monitors. If you find that the software appears to lock up when you click on Save, View Truss, Settings etc. this maybe due to the dialog window coming up off the screen.
To get the dialog window back use Shift, ATL, Spacbar and a dialog window should appear.
Select the Move option.
Your mouse cursor will then change to a four headed arrow.
Move the cursor to the center of the screen and click on any arrow key on your keyboard.
The dialog window will then move to the cursor.