Another way would be using an expression> alt click the stopwatch for position and write in the field
[value[0],460]
the first part value[0] means it will use the value of the 1st dimension, and the second part will be the Y value, in this case 460. Change this to the value you want. In this case the object will be locked in Y at 460 pixels while you can move it in X
I occasionally use this for locking a layer in postion, writing its center position. That way I won’t accidently move it while I can still change its opacity or scale.
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