Swatches: a Shift-click after switching documents starts a new range

The panel cleared its swatch selection when the active document or the
selected art changed, but kept the Shift-click range anchor. A Shift-click
in the other document then selected every swatch from a name clicked in
the first document (for example White) to the clicked one. The anchor is
now cleared with the selection, so the Shift-click selects only the
clicked swatch.

crates/ui-egui/src/panels/swatches/body.rs

@@ -159,6 +159,7 @@ pub(super) fn focus_swatch(app: &VectorcraftApp, ui: &Ui, active: Option<&str>)
     let reselected = last_art.as_ref().is_some_and(|l| *l != art);
     if reselected {
         set_pstate(ui.ctx(), "swatch-selected", Vec::<String>::new());
+        set_pstate(ui.ctx(), "swatch-anchor", String::new());
     }
     let changed = reselected || last_art.is_none() || last_swatch.as_deref() != active;
     set_pstate(ui.ctx(), "swatch-focus", (Some(art), active.map(str::to_string)));

crates/ui-egui/src/panels/swatches/tests.rs

@@ -133,6 +133,21 @@ fn modifier_clicks_select_several_swatches_and_groups() {
     assert_eq!(selected(&ctx), ["Grays"], "a plain click on a group selects it alone");
 }
 
+#[test]
+fn switching_documents_clears_the_swatch_range_anchor() {
+    let mut app = app();
+    let ctx = context();
+    click_tile(&mut app, &ctx, "White", Modifiers::NONE, 0.0);
+    assert_eq!(selected(&ctx), ["White"]);
+
+    app.run("file.new", json!({"width": 200, "height": 200})).unwrap();
+    frame(&mut app, &ctx, vec![], 1.0, show);
+    assert!(selected(&ctx).is_empty());
+
+    click_tile(&mut app, &ctx, "Black", Modifiers::SHIFT, 2.0);
+    assert_eq!(selected(&ctx), ["Black"]);
+}
+
 /// A color swatch or a recent color clicked in the panel becomes the Color Guide's base color
 /// (#3137); a modifier click only selects.
 #[test]