Leaving the Path input field makes the properties dialog disappear

In the quickstart as 'admin', navigate 'To the documents', then to Configuration.

Right click and create a new namespace.

Right click and add a compound type to the newly made namespace.

Add a Primitive field 'Boolean' to that new compound type and click that field in order to display its properties.

Click in the Path property and add 0 (boolean becomes boolean0).

SHIFT+TAB once and see the focus change to the 'Add CSS class' link, and then notice the properties disappears.

NOTE: you must change the value of the Path field to trigger that, SHIFT+TAB'ing out of it is not enough.