Fix disappearing text on Thread view

Changelog-Fixed: Fix disappearing text on Thread view
Closes: #665

damus/Components/SelectableText.swift

@@ -49,6 +49,7 @@ struct SelectableText: View {
         view.isEditable = false
         view.dataDetectorTypes = .all
         view.isSelectable = true
+        view.backgroundColor = .clear
         view.textContainer.lineFragmentPadding = 0
         view.textContainerInset = .zero
         return view

damus/Views/Events/SelectedEventView.swift

@@ -71,6 +71,7 @@ struct SelectedEventView: View {
                 self.bar.update(damus: self.damus, evid: target)
             }
             .padding([.leading], 2)
+            .compositingGroup()
         }
     }
 }