13.19i: distro checks pass on all five; the pickers preview only while open and end on the popup's Hide, as Qt 6.10 changed both

TASKS.md

@@ -497,7 +497,10 @@ Reviews for this section ran on codex `gpt-6.1-sol` at `max` (agent `codex-sol`)
   - 13.19h review: round 1 FAIL: the font scenario emitted the menu's signals itself, Dither and Blur's Radius were set past their controls, the ASCII check took blocks for letters, the mask-alone view was not looked at, and seven rows said more than their scenarios (my rewrite of the table had not landed). Fixed: the font popup opened, hovered and clicked (`popupRow`, `choose`); Dither's style, characters and text size through its sheet and OK, Camera Raw through OK, the Radius typed in the bar, Ctrl+Shift+G and Ctrl+Z as keys, Color Range's OK, Save As from the menu; ASCII of \"@\" must keep holes (inked share under three quarters) and grow about twice at 28; the mask-alone canvas checked black and white; each row says what its scenario does. The reviewer's mutants (no popup, no style handler, blocks for letters, no mask-alone drawing) and a Radius field that writes nothing are each caught.
   - 13.19h round 2: FAIL: the committed Camera Raw shot showed the zero-exposure preview, since the scenario waited for any preview. It now waits for the preview whose ground has brightened; the shot is retaken.
   - 13.19h round 3: PASS.
-  - [ ] 13.19i Distro checks: arch, fedora, fedora44, nixos, resolute.
+  - [x] 13.19i Distro checks: arch, fedora, fedora44, nixos, resolute.
+  - 13.19i work: first run failed on every newer Qt. Arch (6.11), Fedora 43 and 44, Ubuntu 26.04 (6.10) and NixOS (6.11) found two real bugs in the pickers: Qt 6.10 emits `highlighted` when a closed combo box follows its value, so the font menu started a preview as the caret moved and a later close put back text typed since; and it closes the popup on Escape without `hidePopup`, so Escape kept a font or blend preview. Fixed by previewing only while the popup shows and ending on the popup window's `Hide`, tested on both Qts with mutants caught. Two test fixes: `GridSettingsSheetTests` sets an English default locale (6.10's C locale groups nothing), and Dither's starvation test skips off Qt 6.4 as the other five do.
+  - 13.19i second run: all five pass, 334 of 334 each; the full suite passes on the dev image.
+  - 13.19i review: round 1 PASS (the Qt behaviour probed on 6.4.2, 6.10.2 and 6.11.2, six mutants caught).
   - [ ] 13.19j Tag `v1.4.5`; the release workflow publishes every package.
   - [ ] 13.19k Live installs from GitHub in fresh containers.
   - [ ] 13.19l The acceptance checklist.