Pinned tracks still show in their normal location in the timeline goo…

…gle#620 (#90)

* Do not remove track from timeline on pin

* Clearer divide between pinned track area

ui/src/assets/common.scss

@@ -495,6 +495,7 @@ $bottom-tab-padding: 10px;
   // Override top level overflow: hidden so height of this flex item can be
   // its content height.
   overflow: visible;
+  border-bottom:1px solid var(--main-foreground-color);
   box-shadow: 1px 3px 15px rgba(23, 32, 44, 0.3);
   z-index: 2;
   display: grid;

ui/src/common/actions.ts

@@ -734,17 +734,10 @@ export const StateActions = {
   toggleTrackPinned(state: StateDraft, args: {trackId: string}): void {
     const id = args.trackId;
     const isPinned = state.pinnedTracks.includes(id);
-    const trackGroup = assertExists(state.tracks[id]).trackGroup;
 
     if (isPinned) {
       state.pinnedTracks.splice(state.pinnedTracks.indexOf(id), 1);
-      if (trackGroup === SCROLLING_TRACK_GROUP) {
-        state.scrollingTracks.unshift(id);
-      }
     } else {
-      if (trackGroup === SCROLLING_TRACK_GROUP) {
-        state.scrollingTracks.splice(state.scrollingTracks.indexOf(id), 1);
-      }
       state.pinnedTracks.push(id);
     }
   },