Improve number input dialogs #321
Description
2.7's ScaleMenu and #318's IntRangeConfigMenuItem both use JOptionPane.showInputDialog(...) to create a dialog prompting the user for a number.
The dialog accepts any string and gives no feedback on whether the input is invalid.
It would be much more user-friendly to create custom dialogs that don't allow submitting invalid input and give feedback on what's invalid.
Polish could include:
- outlining the input field in red when it's invalid
- displaying a red message explaining why the input is invalid
- not a [whole] number
- not in range
- step buttons