Checking using the direct link: http://slicer.kitware.com/midas3/slicerappstore?os=macosx&arch=amd64&revision=21656

Extensions appears only once.

Is it something systematic ? Or it occurs one every other time ... ?

-it is reproducible
-It occurs on 1-28, 1-30, 1-31 (I do not have older nightlies handy)
-It only occurs if you have at least one extension installed.
-uninstalling all extensions makes the problem go away.
-upon close observation of the process, there is a very short pause before the second set appears in the listing.

Thanks for the feedback. This is very helpful.

Topic has been pushed:

• https://github.com/jcfr/Slicer/tree/2911-prevent-duplicate-listing-of-extensions
• https://github.com/midasplatform/slicerappstore/pull/36

Waiting for review from Midas folks. Will then commit the Slicer changes.

For all revision supporting extensions, no duplicate extension should be listed.

For r < 21660, all extensions will be loaded (no fetch on scroll).

For r >= 21660, extensions should be loaded on scroll properly.
See http://viewvc.slicer.org/viewvc.cgi/Slicer4?view=revision&amp;revision=21660

Fix committed to 2145-support-for-installing-extension-from-file branch.