Improved drag&drop behavior (fixed #1194)
This is a copy from a different part of the workspace? Perhaps add some dartdoc to that effect?
Also, we way want to rename some methods to clarify the types that they take. importResource operates on a workspace resource; importFile and importFolder both operate on DOM filesystem entries. Perhaps change the 2nd two methods to importFileEntry and importDirectoryEntry for clarity?
Added doc. Renamed methods