T-Bar controlled via frontend API always cancels the transition — obs_frontend_set_tbar_position() never updates the T-Bar slider

[michalramus]

Operating System Info

Other

Other OS

Linux Mint

OBS Studio Version

32.2.2

OBS Studio Version (Other)

No response

OBS Studio Log URL

https://obsproject.com/logs/h8qNgQvtJcweSIzm

OBS Studio Crash Log URL

No response

Expected Behavior

After obs_frontend_set_tbar_position() sets the T-Bar to full, obs_frontend_release_tbar() should complete the manual transition — preview becomes live, log shows Manual transition to scene 'X' finished.

The slider position set through the API should also be reflected in the UI and readable back via obs_frontend_get_tbar_position().

Current Behavior

obs_frontend_release_tbar() always cancels the transition instead — program reverts to the previous scene and the log shows Manual transition cancelled, regardless of the position that was set.

The T-Bar slider in the UI never moves, and obs_frontend_get_tbar_position() returns 0 after any obs_frontend_set_tbar_position() call.

Steps to Reproduce

1. Enable Studio Mode, select a non-cut / non-stinger transition, set a preview scene different from program.
2. Advanced Scene Switcher → create a macro with two actions:
   • Transition → Modify T-Bar position → set to full
   • Transition → Release T-Bar
3. Run the macro. → Program reverts to the previous scene; log shows Manual transition cancelled.

Equivalent code:
obs_frontend_set_tbar_position(1023); // full
obs_frontend_release_tbar(); // -> "Manual transition cancelled"

Anything else we should know?

Suggested fix. Make the slider the single source of truth by having the API drive the widget; this reuses the existing signal path and fixes set / get / release / UI at once.