In the ProStructure environment, you can choose to have a default command / tool that remains active after exiting any other present command or tool at use. This Wiki will guide you on how to set up this default tool to remain active after terminating any other previously used command.
1) Navigate to the backstage and choose Preferences at File > Settings > User
2) Now, in the Look and Feel tab, choose the default tool as per your requirement.
NOTE: Currently, only the Selection tool can be set up as a default command. Alternatively, you can choose None to have no command active after terminating any existing command. In this manner, you can set up a default tool to remain constantly remain active / revert to after exiting any ongoing tool.