No properties shown for (basic) attributes / entities

[chaosKP]

Overview of the issue
I created Maven Java Application project, added the Jeddict Modeller and created some simple entities with the designer. Then I wanted to add NamedQueries to the entities and change some properties of the basic attributes.

Expected Outcome
If I left click on the name of an entity or attribute, I get its properties shown on the right side in the Properties space.

Current Outcome
If I click on the name of the entity or on the name of the attributes the Properties on the right side shows "no properties". The same if I do a right click and select Properties there.

The only time I get properties shown are the basic properties if I click on the background or for the two attributes "parentActivity" and "campaign" of the "Milestone" entity.

If I create an Maven Web Application and copy/move the JPADiagram.jpa file there the properties are shown...

Jeddict Version(s)
I tried it in the 5.4.1 bundled with NetBeans 11.2 and also in 5.3 bundled with NetBeans 11.1.

JPADiagram.zip

[Occhioverde]

Same problem in my school's computer on Jeddict 5.4.4 with NetBeans 12.2 and Java JDK 1.8.0 211: as you can see in the attached screenshot, the ID and relation attributes' properties work fine but the basic attributes' ones don't.

I've too tried with older NetBeans, Jeddict and Java versions, but the problem still remains.