The button was parented to the dewar tab but never added to a layout, so Qt painted it at (0, 0) over the TELL sample changer banner. It now sits left of Unmount in the automation row (docked and pop-out), greyed out outside the Queued view like Remove/Clear. A trailing stretch keeps the row's buttons at their natural width instead of sharing the spare space. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>