Currently the following message is displayed when there is only built-in QP available and the user tries to activate a rule not part of any QP :
The rule is already activated on all available quality profiles.
First the message is wrong and second the user has no way of knowing that he should create a new QP before being able to activate the rule.
So we have multiple options there :
1. Update the message in this particular case if we have a way of differentiating both cases
2. Let the user select built-in profiles and show an error message
3. Disable the "activate" button with a tooltip to explain the situation if there is only built-in QP for this language