How to turn off Centre Snapping in Viewer - FCPX

When dragging items in the viewer, the only way to temporarily turn off the "horizon"/center snapping guides (as far as I know) is to hold down the Command key. Pressing the command key should be done after clicking/selecting an object and held down while dragging the object. While an object is an "active selection" (still holding down the mouse button) you can press or release the command key as necessary to activate/de-activate the snapping guides.

In addition to what Tom said:

a) you may try temporarily change the Viewer magnification for added control

b) for minute changes, it may be easier to do it directly in the Inspector: click and drag the number wells up or down to adjust; hold down the option key and drag for a slower more controlled adjustment; or hold down the shift key for quicker adjustment by multiples of ten.

The target button is for the image not for a keyframe. Can you post a screenshot of what you’re doing in the Viewer?

Did you make a feature request?

Use feedback in the Final Cut Pro menu.