Attributes duplicate in case move them to columns and back

[maistrenkoIulia]

Jmix version: 1.0.0-SNAPSHOT
Jmix Studio plugin version: 1.0.SNAPSHOT2838-211
IntelliJ version: IntelliJ IDEA 2021.1.1 (Community Edition)

TC: dynamic attributes>category>create>create 2 attributes
navigate to 'attributes location' tab
set columns count = 2
move each attribute to a separate column
move each attribute back
AR:

[bulgakovea]

can't reproduce

1. Create category
2. Create 2 attribute ( "t" and "t2")
3. Open Attribute location tab
4. Set columns count = 2
5. Moved "t" to Column 1
6. Moved "t2" to Column 2
7. Moved "t" and "t2" back to Attributes column.
   Result:
   

[maistrenkoIulia]

verified