# Segmentation (problem with drawing on a label map)

**URL:** <https://discourse.slicer.org/t/segmentation-problem-with-drawing-on-a-label-map/244>\
**Category:** Support\
**Created:** [May 2, 2017, 1:12pm UTC](https://discourse.slicer.org/t/segmentation-problem-with-drawing-on-a-label-map/244 "2017-05-02T13:12:41Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Sanae\_Akodad](https://avatars.discourse-cdn.com/v4/letter/s/51bf81/32.png) [@Sanae\_Akodad](https://discourse.slicer.org/u/Sanae_Akodad)\
**Post date:** [May 2, 2017, 1:12pm UTC](https://discourse.slicer.org/t/segmentation-problem-with-drawing-on-a-label-map/244/1 "2017-05-02T13:12:41Z")

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Hi everyone,

I’m using the 3D Slicer to make segmentation based on T1 images. I have select by drawing the white matter and then the grey one. While I was drawing the cerebellum, I made a quick recheck of what was already done in the cortex and suddenly all the areas that I’ve drawn disappear. The grey and white matter are used as a label map and T1 images from MRI are used as the master volume.

Does anyone know what could be the cause of the invisibility of what I draw before.

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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:** [May 2, 2017, 5:22pm UTC](https://discourse.slicer.org/t/segmentation-problem-with-drawing-on-a-label-map/244/2 "2017-05-02T17:22:40Z")

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Do you use the latest nightly version of Slicer?