Current find usages correctly finds all usages through "." operator for Collection/Map - typed variables/fields, read/write filters filter reads/writes to the collection field/variable.

Sometimes it would be also useful to track reads and writes of the Collection through add/remove/set/put methods. This would probably result in additional filter buttons on the Find Usages Result display.

queries for size, empty, contains could be treated either as separate operations, or part of the 'read': the first option would really filter read operation of collection *items*, the second option would just separate collection mutations from read access. 

The same feature could be useful for arrays: read from within the array and write to array element, semantic the same as for List.get() / List.set().