[e4-dev] Proposal to replace the 'visible' flag

[Eric Moffatt <emoffatt@xxxxxxxxxx>]

After spending some time with Lars yesterday
explaining the difference between the 'toBeRendered' flag and the 'visible'
flag (again!) I think that I've come up with a way to eliminate it altogether...

The proposal below is a first cut so
I'd appreciate feedback on whether everybody thinks this is a good approach,
if the new field name is clear...

Background: The 'visible' flag's intent
is to allow the UI to take over the control of some element's widget so
that some other part of the UI can use it. It's currently used when a stack
is minimized, allowing the ToolControl to show the stack in its 'popup'.
if 'visible' == false then the element is removed from the UI presentation
in preparation for its use somewhere else in the UI. Unfortunately the
name is misleading at best and has caused confusion in just about everybody...

Iin order to support the Perspective
story UIElements already have a 'curSharedRef' flag which is how we designate
which Placeholder 'owns' the shared part. This seems to be a much clearer
way to express the semantic "I own that element's widget'... so I
propose:

- Removing the 'visible' flag altogether
- Renaming 'curSharedRef' to something
like 'logicalParent' (i.e. the element that 'owns' the referenced element,
including its widget)

If 'logicalParent' == null then the
element's 'actual' parent owns the control (i.e. it's in the regular UI
presentation), if not then it is removed from the regular UI presentation
and is expected to be managed by its 'logical' parent.

Onwards,
Eric