To reproduce:
-add a control(button, text field or whatever) to the content panel
-go to "Layout" panel
-place pointer over "Min Width" input text field, press mouse button, remove field content, enter some value (do not press enter!)
-place pointer over "Max Width" input text field, press mouse button, remove field content, enter some value
-press Enter
It's expected that value of field will apply to the control when text field loose focus, but, as you can see, when you press Enter button, value of "Min Width" returned to it's previous state.