See the T834791 ticket.
Ribbon - TdxRibbonGalleryItem - Switching a gallery item's Enabled property resets the gallery's scroll position
Answers approved by DevExpress Support
We have fixed the issue described in this ticket and will include the fix in our next maintenance update. To apply this solution before the official update, request a hotfix by clicking the corresponding link for product versions you require.
Note: Hotfixes may be unavailable for beta versions and updates that are about to be released.
Thank you for sharing your test results. This enhancement will make our gallery even more useful.