Negative points in checklist creation requires using point notation

[maarila]

Defining how many points a checklist item gives requires using point notation for negative numbers. In other words, typing '1,5' works, typing '-1,5' does not.

The problem can be circumvented by defining negative points using dot notation: '-1.5'.

How to reproduce:

1. Add a new checkbox to a checklist.
2. Type in points such as -1,5.
3. Remove focus from point box with tab or mouse click.
4. Points on the box are reset to zero.

[hisahi]

Cannot reproduce in this exact way; -1,5 sometimes works, 1,5 never does. Comma notation seems to be locale-specific, if anything.