On this site, I constantly see heaps of people saying that the undo button is broken. Saying it undoes more steps than they want it to, it undoes heaps and heaps of work and sets them back an hour, or undoing has caused the plane to duplicate 6 times and 2 of the duplications have turned pink.

I've played SP since it's release, on 2 iPads, an android phone, 3 Windows PCs and a MacOS device, and on literally all of those platforms, my undo button has been fully functional and usable. For a long time I was wondering why everyone gets so many issues with it, but lately I've been watching people build while streaming on discord and talking to people about the problems that they have, and I've come to the conclusion that they're not using it correctly.

The way the undo button works is, once you've done certain things, the game saves the steps you've done, and when you undo, the game goes back to the save that is prior to the latest save. The only problem is, this "step saving" thingy doesn't happen after doing every step.

Here's the logic:

• It doesn't count when you use designer enhancement mods, such as DesignerSuite, Overload and Fine Tuner.

  This is the most common silly thing that I see people complaining about saying the undo button doesn't work. From what I've heard, getting designer mods to work with the undo button isn't actually possible. Thus... yeah. Also this is why I never use fine tuner to rotate individual parts lol.

• If you edit the shape of a fuselage, it counts all edits you've done with the menu open as 1 step, even if you adjust the shape of multiple parts and click on other ones.

• All nudging and rotating using the tinker panel is 1 step, even if you've gone back and forth and selected different things and parts while still in the tinker panel.

• Every time you drag a part it counts as a step

• Every time you grab a new part or delete a part, it counts as a step (unless you grab a new part and drag it straight to the bin without dropping it, then it doesn't count)

  If you've done some XML modding and want to step save it, grabbing a new part, dropping it, and then deleting it is a good way to save it.

• Every time you rotate a part normally, it counts as a step (using WASD or arrow buttons)

• Painting your craft counts as a step (closing the paint editor is what sets the step)

• Editing the text on labels doesn't count as a step

• If you go back, it will go 2 step saves ago, so if you go forward a step, it will go back to when the game did the last step save, so if you go back and it undoes way too much, try going forward a step, it might bring you to where you actually wanted to go.

• Connection editing does not count as a step (this includes reattaching or pressing shift+K

• Spamming the undo button heaps of times before the first undo has loaded is going to cause your plane to duplicate and do weird garbage like turning pink. Only press the undo button once, and wait for that undo to complete before pressing the button again.

Okay, the undo button definitely isn't perfect. I really wish it would add steps when you're changing between fuselages when you're adjusting, their shape, I wish it would save steps when you go between nudging and rotating when you're using the tinker panel, I wish it would save a step when you close overload, and I wish it would save when you edit connections. But it doesn't which is annoying.

Another thing to note that might help you remember this is, back in version 1.1, the undo button worked seamlessly for pretty much everything. But as new things have been added to the game, making them work with the undo button seems to have fallen by the wayside, to where certain things thatvreally should work as a step... don't.
So basically the newer the thing is in the designer... the less likely it's going to make a step save.