Shortcuts: a modifier key press is never the key that typed a text

In the web build, pressing Shift and then a letter in one frame sends the Shift press, the
letter's text and then the letter's key press. The text paired with the Shift press as the press
before it, so a key-position shortcut looked up Shift instead of the letter, and a held Shift's
repeated presses dropped the text as a repeat. Modifier key presses now never pair with a text.

crates/ui-egui/src/shortcuts.rs

@@ -848,12 +848,13 @@ fn latin(text: &str, physical: Option<Key>) -> String {
 
 /// For each event, the index of the key press that typed it when it is text: the press right
 /// before it (egui-winit) unless an earlier text took that press, or else the press right after it
-/// (eframe's web build with no text field focused). Each press types at most one text. A text
+/// (eframe's web build with no text field focused). Modifier key presses type no text. Each press
+/// types at most one text. A text
 /// takes the press after it only when every later text in the same run of alternating texts and
 /// presses has a press after it too; otherwise the text after that press takes it as the press
 /// before it, and this text has none.
 fn typing_presses(events: &[egui::Event]) -> Vec<Option<usize>> {
-    let is_press = |k: usize| matches!(events.get(k), Some(egui::Event::Key { pressed: true, .. }));
+    let is_press = |k: usize| matches!(events.get(k), Some(egui::Event::Key { key, pressed: true, .. }) if !is_modifier(*key));
     let is_text = |k: usize| matches!(events.get(k), Some(egui::Event::Text(_)));
     // Whether the run of alternating texts and presses that starts with the text at `j` ends
     // with a press.

crates/ui-egui/src/shortcuts/tests.rs

@@ -1491,6 +1491,8 @@ fn one_key_shortcuts_use_the_key_of_the_same_keystroke_in_either_order() {
     assert_eq!(typing_presses(&[text("p"), press(Key::V), text("м")]), [None, None, Some(1)]);
     frame(&mut app, vec![text("p"), press(Key::V), text("м")]);
     assert_eq!(app.session.tool_id(), "selection", "the text after the key uses it");
+    // A modifier key press does not type text, so the web text after Shift uses the key after it.
+    assert_eq!(typing_presses(&[press(Key::ShiftLeft), text("З"), press(Key::P)]), [None, Some(2), None]);
     let names = |events: &[egui::Event]| -> Vec<String> {
         shortcut_presses(events, Modifiers::NONE).into_iter().filter_map(|(n, _)| n.into_iter().next()).collect()
     };