Unexpected Tab Key behavior

Hi,
Newbie with MPS.

I have noticed the following behavior with Tab Key which in mapped to Tab KeyMap in MPS settings:
1) If a cell editable=false, means we cannot edit the cell but we can modify the cell with ctrl+space. If we press Tab on a series of such cells it will skip those cells and move to next editable cell but as expected it should move to cell with editable=false.
2) If cell read-only=true, means cell is in read only mode we cannot modify the cell. If we press Tab on a series of such cells it will move to those cells one by one but as those cells are read-only as expected it should skip those cells with read-only=true.

So it behaves opposite as expected.

Thanks,
Lokesh