Improve Problems view filter dialog UX and fix vanishing markers

This commit addresses several usability issues with the Problems view
filter configuration dialog:

Fix: Markers vanish when filter scope depends on selection
When the filter scope was set to 'Selected resource', 'Selected and
children', or 'Same project' and no resource was selected in the
explorer, selectByScope() would return false for all markers, making
them all disappear. Now, when no resources are selected, these
selection-dependent scopes fall back to showing all markers (ON_ANY
behavior) instead of showing nothing.

UX: Replace scope radio buttons with compact combo dropdown
The 5 verbose radio buttons for scope selection are replaced with a
single Combo dropdown that takes much less vertical space. The working
set 'Select...' button is shown/hidden dynamically based on the
selected scope. Mnemonic characters are stripped from labels since
they are not applicable in Combo items.

UX: Disable configurations when 'Show all items' is checked
The configurations group is now properly disabled when 'Show all items'
is checked, making it clear that individual filter settings have no
effect in that mode.

UX: Collapse advanced filter sections by default
The type filter configuration (which most users rarely change) now
starts collapsed, while scope and severity/description remain expanded.
This reduces visual clutter for the common case.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: vogella

bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/FiltersConfigurationDialog.java

@@ -233,6 +233,9 @@ private void updateShowAll(boolean showAll) {
 		updateConfigComposite(!showAll);
 		updateLimitTextEnablement();
 
+		// Disable the configurations group when showing all items
+		setEnabled(!showAll, configComposite);
+
 		if (showAll) {
 			previouslyChecked = configsTable.getCheckedElements();
 			configsTable.setAllChecked(false);
@@ -414,10 +417,16 @@ private void createConfigDesc(Composite parent) {
 
 		configAreas = generator.createFilterConfigurationFields();
 
+		// Scope and severity/description are always expanded (most used)
 		createFieldArea(toolkit, form, scopeArea, true);
 		Iterator<FilterConfigurationArea> areas = configAreas.iterator();
+		boolean isFirst = true;
 		while (areas.hasNext()) {
-			createFieldArea(toolkit, form, areas.next(), true);
+			FilterConfigurationArea area = areas.next();
+			// First config area (severity/description) is always expanded,
+			// subsequent areas (types) start collapsed to reduce clutter
+			createFieldArea(toolkit, form, area, isFirst);
+			isFirst = false;
 		}
 	}
 

bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/MarkerFieldFilterGroup.java

@@ -649,6 +649,11 @@ public boolean selectByFilters(MarkerEntry entry) {
 
 	public boolean selectByScope(MarkerEntry entry, IResource[] resources) {
 		int scopeVal = getScope();
+		// When no resources are selected and scope depends on selection,
+		// fall back to showing all markers to avoid confusing empty results
+		if (resources.length == 0 && scopeVal != ON_ANY && scopeVal != ON_WORKING_SET) {
+			return true;
+		}
 		switch (scopeVal) {
 		case MarkerFieldFilterGroup.ON_ANY: {
 			return true;