Improvement Suggestion: Pin/unpin multiple Items at once

This request affects also other rightclick features such as check-in/out. If an action is possible for each element of the selection and does not require further user interaction (like create relation) it should be also possible for the whole selection.

This request affects also other rightclick features such as check-in/out. If an action is possible for each element of the selection and does not require further user interaction (like create relation) it should be also possible for the whole selection.