Repreducing steps:

• Select a non  Qml file from the project view
• click return to design to try to go back to the Design view
• You will be directed to the welcome page instead
• there the Return to design button does not perform any action
• when trying to open the project again to select a qml file, the "could not open files of type inode/directory" error will show up
• have to close/reopen design studio to open the project again