# Operations on segments that are not visible

**URL:** <https://discourse.slicer.org/t/operations-on-segments-that-are-not-visible/14161>\
**Category:** Development\
**Created:** [October 20, 2020, 2:05pm UTC](https://discourse.slicer.org/t/operations-on-segments-that-are-not-visible/14161 "2020-10-20T14:05:30Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![hherhold](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/hherhold/32/12199_2.png) [@hherhold](https://discourse.slicer.org/u/hherhold)\
**Post date:** [October 20, 2020, 2:05pm UTC](https://discourse.slicer.org/t/operations-on-segments-that-are-not-visible/14161/1 "2020-10-20T14:05:30Z")

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I will sometimes inadvertently hit “apply” on an editing operation with a segment that is not visible. This results in a rather long delay, followed by “undo”, to get back to where I was.

Has there been any discussion about a warning box when you hit “apply” and the selected segment is not visible? I realize it’s my own dumb fault, but over the years this would probably have saved me a fair amount of time.

Thanks!!

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**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [October 20, 2020, 2:54pm UTC](https://discourse.slicer.org/t/operations-on-segments-that-are-not-visible/14161/2 "2020-10-20T14:54:06Z")

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This has come up a few times before. I agree that applying operation on a non-visible segment often happens by mistake, so a warning box for could be helpful. If we add a “Do not show again” checkbox then it would not be very annoying for those people who do this intentionally. Could you submit a feature request to [https://github.com/Slicer/Slicer/issues](https://github.com/Slicer/Slicer/issues)?

Would you be interested in implementing it? It would be a helper function in C++ that could be called using a single line from both C++ and Python scripted effects.

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**Author:** ![hherhold](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/hherhold/32/12199_2.png) [@hherhold](https://discourse.slicer.org/u/hherhold)\
**Post date:** [October 22, 2020, 12:25pm UTC](https://discourse.slicer.org/t/operations-on-segments-that-are-not-visible/14161/3 "2020-10-22T12:25:03Z")

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Feature request submitted.

Sure, I’d be willing to try implementing it. As long as nobody needs it urgently - I have two separate conference talks to prep and give in the next month or so.