Issue Summary

As noted by @davidlamhauge (Thank you!)
The range feature numerical input spinboxes are turned ON when the program starts, and only resume their normal behaviour after deactivating the range checkbox once.

I'd say it's not wanted behaviour. It really depends on how people approach the feature itself, however it may be more logical and clear to the user to only enable the spinboxes when the checkbox is turned and deactivate them when the checkbox is not ticked.

Steps to reproduce

1. Open Pencil2D
2. Note the range numerical input start / end spin boxes are active
3. Turn the range function ON by ticking the checkbox
4. Turn the range fucntion OFF by ticking the checkbox. Notice that the input boxes are greyed out.

System Information

• Pencil2D Version:

Version: 0.6.2
commit: ecbe853
date: 2018-10-05_13:12:56
Development build
Operating System: Windows 7 SP 1 (6.1)
CPU Architecture: x86_64