Custom Cuts Very Sluggish Since 2.5.3 and 2.5.4

I see why it’s slower. Two things changed:

  1. When you move the slider using a key, each time you move it it copies the timestamp to the clipboard. This is probably causing the slow down, especially if your clipboard is being shared with other apps:
  1. We’ve added key modifiers to fine tune how the keys respond, if you want to move faster use the shift key or the ctrl key. See this feature addition:

Does the second feature help you?