[Property Sections] Validate the syntax of complex expression or disallow direct editing
Problem description
AFAIK, input validator are responsible for syntax checks and alike,
whereas the validation on save is responsible for more complex tasks
such as symbol checking.
However, the sytax checking is only “really” performed for integers and
float data types. For enums, or structs, arbitrary strings can be
entered. This causes a suboptimal UX.
Resolution
Either implement a syntax check based on the expressions, or just forbid editing in these cases and just disply the result from the edit dialor
(from redmine: issue id 3585, created on 2018-11-30)