Redmine Table Calculation

A data sheet should have a 'Clear Cache' button when it works with calculations in order to allow the user to clear the cache on demand.

The caching mechanism of a data sheet will be cleared automatically as soon as a user will save an entry. Consequently, changes to the data sheet coming from configuration in admin area won't trigger a rebuild of the page.

Those changes may happen when an administrator would add a calculation to a table or add further columns to be calculated with. As long as the cache won't be cleared a user could not see these changes on her data sheet. The 'Clear Cache' button would help to clear the cache in those situations.

Requirements:

1. The button should only be visible when the user is allowed to edit the table.
2. The button should only be visible when 1. and a calculation for the table exists.
3. The button should be implemented as menu item in the context menu (tree-dots-menu) of a data sheet.