SearchableList: re-rank while typing, and make Enter confirm the best match

[Copilot]

SearchableList<TItem> drew its search box with ImGuiInputTextFlags.EnterReturnsTrue. With that flag, ImGui only writes the edited text back on Enter or when the box loses focus, so searchTerm stayed "" while the user typed and the list never re-ranked. Enter then confirmed cachedValue ?? selectedItem before the list was ranked against the new term. That was the first unranked row, or the default item if one was passed. Typing Cherry and pressing Enter confirmed Apple.

Changes (ImGui.Popups/SearchableList.cs)

• Search term updates live: the search box no longer uses EnterReturnsTrue, so searchTerm changes on every keystroke and the ranking follows it.
• Enter is detected separately: it counts when Enter/KeypadEnter is pressed while the box is active or was just deactivated. Single-line Enter deactivates the box in that same frame, so checking only for active would miss it.
• Enter is handled after ranking: it runs after the list box has ended, using the ranked list.
  • With text typed, it confirms the top-ranked match, even if a different item was the current choice.
  • With nothing typed, behaviour is unchanged: it confirms the current choice, or the first item if there is none.
• The ranked result is now held in a list, because it is read twice: once to draw the rows and once for Enter.

ImGui.InputText("##Search", ref searchTerm, 255);
bool enterPressed = (ImGui.IsItemActive() || ImGui.IsItemDeactivated())
	&& (ImGui.IsKeyPressed(ImGuiKey.Enter) || ImGui.IsKeyPressed(ImGuiKey.KeypadEnter));
// ...rank, draw list...
if (enterPressed)
{
	if (!string.IsNullOrEmpty(searchTerm) && sortedStrings.Count > 0)
	{
		cachedValue = itemLookup[sortedStrings[0]];
	}

	ConfirmSelectedItem();
}

Tests (tests/ImGui.Popups.Tests/SearchableListTests.cs)

New cases:

• Typing Cherry moves the Cherry row above Apple.
• Typing Cherry then pressing Enter confirms Cherry, with no current choice and with Apple as the current choice.
• Enter with nothing typed confirms the current choice, or the first item when there is none.

The first three fail against the previous implementation.

• Fixes SearchableList popup: typing in the search box doesn't re-rank the list, and Enter confirms the first item instead of the best match #565

[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud