feat: add menu option to pop up the selector window

alt-tab-macos/ui/Application.swift

@@ -64,6 +64,11 @@ class Application: NSApplication, NSApplicationDelegate, NSWindowDelegate {
         Screen.showPanel(preferencesPanel!, Screen.preferred(), .appleCentered)
     }
 
+    @objc
+    func showUi() {
+        showUiOrCycleSelection(0)
+    }
+
     func cycleSelection(_ step: Int) {
         TrackedWindows.focusedWindowIndex = TrackedWindows.moveFocusedWindowIndex(step)
         self.thumbnailsPanel!.highlightCellAt(step)

alt-tab-macos/ui/StatusItem.swift

@@ -9,6 +9,11 @@ class StatusItem {
                 withTitle: "Preferences…",
                 action: #selector(application.showPreferencesPanel),
                 keyEquivalent: ",")
+        item.menu!.addItem(
+                withTitle: "Show…",
+                action: #selector(application.showUi),
+                keyEquivalent: "s"
+        )
         item.menu!.addItem(
             withTitle: "Quit \(Application.name) #VERSION#",
                 action: #selector(NSApplication.terminate(_:)),