TagBox: Fix tag label display when valueExpr is set to function and hideSelectedItems is enabled (T1234032) (Draft)

[jdvictoria]

No description provided.

[AlexanderMoiseev]

JFYI: there is a way to fix it on selection.strategy level i believe, but, as long this bevavior with hidden items is possible only with tagBox, i thing this WA will do. I was looking for solution with selecteion first, but decided not to tamper with base functionality

[ksercs]

[missed scenarios, local solution]

I agree with Alex - this issue is mostly expected to be fixed not on a TagBox level. I see that proposed solution works in the target scenario but I cannot find a reason "why ideologically it should work this way?".

I believe we cannot accept this solution because it assumes that whole hideSelectedItems prop processing was incorrect, but I see it worked well when valueExpr is not a function => the reason of the issue is related to the valueExpr option processing and mostly it's not on a TagBox level.

Previously algorithm checked if necessary items are already loaded (are in plain items) and then just render it or additionally loaded dependent on an answer. After your change the code always believes items are already loaded and just renders them - sound not correct. Example of a broken scenario: just set some value in initial config.

Let's try to find a real reason this way:

• create two sample pages - with broken behavior when valueExpr is a function and with a correct behavior when valueExpr is a string
• debug both and find the difference - when exactly we get some unexpected result (mostly it's related to list selectedItems or like this)
• find why we get this incorrect result and fix (mostly somewhere in collection strategy)

Please don't forget to write separate tests additionally, at least for the scenario mentioned above.
Also wanna remind you that we will need to write a test for place where the fix is applied (for collection if the fix is on collection level).

[ksercs]

[excess operation]

This condition is excess: if initially property is true, setting it to true at runtime will do nothing

[ksercs]

[repeatable code style mistake]

Constants please!