disable menu button of current track on loading

src/assets/scss/5-modules/controls.scss

@@ -96,6 +96,10 @@
   font-size: 0;
 }
 
+.controls__menuBtn.disabled {
+  color: rgba($color-primary, .4);
+}
+
 .controls__menuBtn svg {
   width: 2.5rem;
   height: .5rem;

src/components/Controls.svelte

@@ -25,7 +25,13 @@
 
     <div class="controls__menu">
         <Popper>
-            <button slot="btn" class="controls__menuBtn" aria-label="track menu"><IconMenu></IconMenu></button>
+            <button
+                slot="btn"
+                class="controls__menuBtn"
+                disabled={!$current}
+                class:disabled={!$current}
+                aria-label="track menu"
+            ><IconMenu></IconMenu>{!!$current}</button>
             <div slot="content" class="contextMenu__list">
                 {#if $current}
                     <ContextMenu track={$current}></ContextMenu>