Fix update activity description ambiguity
Created by: ederag
Allow entering description either from the activity line or from the description box, but not both (fix issue #305 (closed)). Prevent saving and give warning in case of ambiguity.
In activity line only, "valid" check mark icon to the right
Both in activity line and in description box: ambiguity (which one to use ?), "error" check mark icon More information in the icon tooltip (hovering mouse on the icon)
In description box (multiple lines allowed there), "valid" check mark icon
When editing an existing fact, the description is now only displayed in its box.