Make it possible to select every existing flag in "Advanced Search"
Currently the dropdown-list in "Advanced Search" only provide a limited amount of flags to search for.
For example missing are:
They can be searched in the "Simple Search" but are not in the dropdown-list of "Aggregated Search".
Additionally it might be nice to have the option to search for the "Additional Flags" as well. So far i cant find any way to do this.