Current behavior:
Access level (Read/Write mode) of TMs can only be set from the project settings when attaching a TM to a project.

Available workaround:
Set TM in Read or Write mode when attaching the TM to the project.

Requested behavior:
There is an option in the TM settings to always use the TM in Read mode (or Write mode) by default.

Use case:
Some organizations wish to use certain TMs in Read mode only, however, when manually assigning TMs to a project, it can be easy to make a mistake and set the incorrect mode for the TM.