Validation error doesn't surface on Title field

[andrewandante]

BaseElement combines Title and ShowTitle into one instance of TextCheckboxGroupField. If you require this field, and don't fill it out, the element will throw a Validation Error but not show you where - seems to be hidden by combining the fields.

[lerni]

Just ran into this. If inline_editable is enabled, it even ignores the required field 😞 Setting a Title is essential for the use with dnadesign/silverstripe-elemental-virtual but ATM it looks like you cannot make Title a required field.

[michalkleiner]

Increasing the impact to accommodate not being able to require the field when inline editable.

[GuySartorelli]

@michalkleiner fyi the lack of validation for inline editable blocks is already raised separately in #699

[maxime-rainville]

I don't see any scenario where we fix this without fixing #329

I'm going to call this one a duplicate.