I have a series of dropdowns that depend on a value being present in the previous one. For example the Brand 2 dropdown would not be enabled if Brand 1 dropdown was blank/empty. Same with Brand 3. It relies on Brand 2 having a value. But as you can see from the screengrab below I can go back and delete the value in Brand 2 and while Brand 3 becomes disabled it still holds a value.

I've previously implemented something like this before but with combo boxes. i used this bit of code for the DefualtSelectedItems.
If(Self.DisplayMode=DisplayMode.Edit && !(IsBlank(Brand2_CB_1.Selected.crfeb_brandname)), {crfeb_brandname:Parent.Default}, Blank())
This worked great for combo boxes but now, using dropdowns, I do not have an option for DefaultSelectedIitems and using this code in the Default field doesn't work. I get an 'Expected Text value' error. How could I make that Brand 3 dropdowns not only dependent on the Brand 2 dropdown to be enabled but also to clear its value if the Brand 2 dropdown is reverted back to blank?