When for whichever reason no mode is selected, Release, Debug or else, and you press the compile 'Project Options' button, appears a message that invites to select a mode, but pressing any button the IDE hangs.
The only mode to solve is to kill the IDE process.
I.e. it happens when opening an old project and its conversion to the new format, or when creating a new project in a workspace.
It was already present with older versions where the mode selection was present.
The picture shows what happens.
EDIT:
How to reproduce:
1- Create a project standalone (not in a workspace)
2- from menu choose: File => new_Project (you can also use the toolbar 'new' icon then choose 'project')
3- From the new project dialog select 'add to existing workspace'.
4- the freshly created project is added to the just created workspace with no mode selected.
5- press the 'Project Options' button and get the IDE hangout.
I can't exclude that there are other ways to produce the problem.