(4.10.1 Linux) Fixture editor: Bug when adding capability

[polemon]

I guess I'll start how to reproduce the bug first, since that makes explaining easier:

1. Open qlcplus-fixtureeditor
2. Click on "New"
4. Switch to page "Channels"
5. Click on the green "+"
6. Name it something, e.g. "test"
7. Click on the green "+", to add a new value to the capabilities list
8. Set Min to "0" and Max to "0"
---> It is now impossible to add another capability by clicking the green "+"
Even after clicking "OK", and bringing up the capability menu up again, it's impossible to add anything to that list.

Why this is a problem:
I have a fixture, which has a function on value 0 and only on value 0. The function is not accessible on any other value, like 0 to 3 or something.

This problem also becomes apparent, when it's just another single channel function, eg Min 10 - Max 10. It becomes impossible to add anything to the list, and the fixture editor seems to try to fill the channel up to that value, when clicking on the "+" another time.

It seems to me it is a sort of checking fault, where this slipped through testing.

It is possible to assign values like [0-10], [16-12], and [20-30] (having Min higher than the Max value). When setting the values like this, it also becomes impossible to add further capabilities by clicking the green "+".

Suggestions:
- It should be impossible to have values that are Min > Max.
- It should be possible to have capabilities that occupy only one value.
- Maybe a little more visual feedback, when entering overlapping values. (they seem to revert back to their previous value when I leave the text field, but still).

[mcallegari]

This is all fixed on GIT,

Either build from sources, use an automated build or wait for 4.10.2.