Connections cannot be added, opening Connection Editor crashes DS

Found issue:

Connections cannot be added in Connections view -> Connections since the dialog does not show any content / nothing can be selected from the menus. Opening Connection Editor crashes Design Studio

Steps to reproduce:

• Create empty project
• Open Connections view, Connections tab
• Select the existing connection for button component by clicking it
• -> Dialog that opens, does not show content for target etc and nothing can be selected from Target and Signal menus (see attached pictures connections_45, and connections_44 for comparison)
• Clicking "Jump to code" does nothing
• Clicking button to open Connection Editor, crashes Design Studio