Bugfix
A theme can define a variable without storing a value for it. In this case, the possible default value of the variable counts. If you overwrite such a variable (e.g. an HTML template for a control) in a new theme in the theme editor, the override is also marked with "abstract" and has no effect.
Test
- Create theme.
- Overwrite inherited variable that has only default value.
- Reload theme.
- The overwritten value of the variable must be displayed and used.