form view of attribute table unusable with more than a few relations

[beerockxs]

The form view of the attribute table locks QGIS up if you have more than just a few relations, because the expandabable sub-form for each relations start out expanded instead of collapsed. Each sub-form shows all of its sub-forms by default, Can this be changed to start out collapsed? That way, even complex sets of layers with multiple relations can be used with the form view of the attribute table.

QGIS version	3.15.0-Master	QGIS code revision	48619cf552
Compiled against Qt	5.11.2	Running against Qt	5.11.2
Compiled against GDAL/OGR	3.2.0dev	Running against GDAL/OGR	3.2.0dev
Compiled against GEOS	3.8.1-CAPI-1.13.3	Running against GEOS	3.8.1-CAPI-1.13.3
Compiled against SQLite	3.29.0	Running against SQLite	3.29.0
PostgreSQL Client Version	11.5	SpatiaLite Version	4.3.0
QWT Version	6.1.3	QScintilla2 Version	2.10.8
Compiled against PROJ	7.2.0	Running against PROJ	Rel. 7.2.0, November 1st, 2020
OS Version	Windows 7 SP 1 (6.1)	This copy of QGIS writes debugging output.
Active python plugins	SpreadsheetLayers; db_manager; MetaSearch; processing

[Dominique101]

I would like to know if this issue is still active. I have the same problem, loading times for the attribute table form can become very long, if the object has multiple relations. It would be great if it was possible to change the default behaviour, so the relations are collapsed (and loaded lazily) instead of extended when the form in the attribute table opens.

Alternatively, it would help if it was possible to limit the recursion depth to 1. Meaning, a relation in a sub-form should not continue to load its respective relations and expand them.

For my use case, it would be great if these options were accessible via PyQGIS or QGIS.ini.

[gioman]

@Dominique101 ticket is open, so it is still active.