GIMP Version: 2.8.4
Operating System: Windows
OS Version: Windows 8
GIMP Experience: Basic Level

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All right, this has to be the most bizarre problem I've had so far. I was working on an image, right, inking and colouring this dude. When I was almost done with it, I just sorta doodled some with a different colour all over it to try out some contrasting colours, which I had every intention of ctrl + z-ing away immediately afterwards. Only it just.. KINDA did. In a square shape on like.. his chest! No matter how far back in history I go - "regretting" away everything else on him - the parts I just added are visible everywhere except in that square space on his chest!

I would probably be angrier about all the work lost if I wasn't absolutely dazzled by this remarkable circumstance!

So my question becomes: what the heck?! Is this a feature I accidentally triggered with like.. my elbow and knee when getting up to go fetch some coffee? I don't get how this is even possible. All of the colour - midtone, highlights and shadows - are on the same layer, by the way.

Maybe it's a ghost, have you tried to flatten and export the image to check it out ?

Yeah, it was definitely there on the layer. I could sample it with the colour picker and everything.

I had:

Ink layer
colour layer
sketch
background

Sketch was hidden at the time, and all the colour work I did was on the colour layer. Hiding and making the others visible changed nothing. Resizing the image or dragging it off screen didn't "wipe it clean", and even undoing things back to when he was black and white - save for the areas with the new brush on them - and saving a copy of it would have it show up on the copy.

*Incredibly* bewildering. A true urban mystery.

If this were to happen to me, I would suspect a hardware error; in particular a bad memory chip.

It's not a hardware or graphics glitch. It's a software issue where Gimp doesn't register it as a change in the document's history, and I've finally reproduced it.


A recap of the problem: You draw a line or do an adjustment, and when you undo, you undo the change prior to the one you're trying to undo. There is no way to undo the latest thing you did, and even if you undo the entire document all the way back to a blank page, your line/adjustment remains.

Cause: If you draw a line with a basic brush, for instance, and you don't "release" (let go of mouse button, lift pen off tablet) but rather "draw" into/onto a UI box (the tool box for example) and end the line there, the line will appear on the document but not in the undo history. It will be assigned to the layer you drew it on, and to my knowledge it's impossible to get rid of without erasing what is underneath it on the same layer also. Suffice to say, this can *completely ruin* a layer for you if you're not careful.

So, I have no solution if this happens to you, but at least this way you can take precautions to avoid it.

Doing this works as it should for me (GIMP 2.8.2 running on Slackware).

Hmm. Interesting. I'm a little busy right now, but I'll see if I can replicate it on video and re/confirm what causes it. Perhaps it's specific to other UI elements, and doesn't in fact happen with the tool box.

I opened a new layer grabbed the paintbrush and painted all the way to the tool box.I selected edit>undo and it worked for me.

Windows -Vista Home Premium 32 bit
I also tried with the calligraphy pen tool but this time 2 lines.Both undos worked.

Yeah, I uh... I dunno why it WORKS now. I could consistently replicate it when I posted, but there must be some other variable I don't know about. Something unique to that session.

If I happen across it again, I'll be sure to trace my steps backwards and see if I can figure it out.