Fix right click handler for tabs

Also, some fun test helpers

Co-Authored-By: Mikayla <mikayla@zed.dev>

crates/ui/src/components/tab.rs

@@ -37,8 +37,11 @@ pub struct Tab {
 
 impl Tab {
     pub fn new(id: impl Into<ElementId>) -> Self {
+        let id = id.into();
         Self {
-            div: div().id(id),
+            div: div()
+                .id(id.clone())
+                .debug_selector(|| format!("TAB-{}", id)),
             selected: false,
             position: TabPosition::First,
             close_side: TabCloseSide::End,