Sharing icon is not updated if document is shared with "Modify" rights

The "Sharing" icon for a document in the "My Documents" screen is grey by default (document is not shared).
The icon turns to blue if the document is shared with "Read" permissions.
The icon stays grey if the document is shared with "Write" permissions.

The icon should turn at least to blue to indicate that the document is shared.
Preferrable would be to even turn to a different color (e.g. red) for write permission, to be able to differentiate.