Please provide clear reproduction steps for your issues, maybe with screenshots if that helps visualizing the problem you are encountering.

I think I see an issue now that was introduced by relaxing the grab point calculation a bit (see changelog item "Improved behaviour when dragging a timeline item in the sample editor and the initial grab point wasn't exactly the horizontal position of the item." for OpenMPT 1.30.03.00). I think it works as intended when the sample is zoomed out but when zooming in, the new behaviour is not very practical. Can you confirm that you only see this issue when zooming into the sample? If not, I still need better reproduction steps because to me, the behaviour feels "natural" when zooming out.

Drawing and dragging stuff around should now behave more predictably again when zooming into the sample as of r17143. You can grab a test build from https://builds.openmpt.org/builds/ (available in a few hours) or setting OpenMPT's update channel to "Next".

No feedback -> assuming fixed.