Minor UI fixes

app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryAdapter.kt

@@ -77,10 +77,12 @@ class LibraryAdapter(private val fragment: LibraryFragment) : RecyclerViewPagerA
     }
 
     /**
-     * Returns the position of the item. Always assume the position has changed.
+     * Returns the position of the view.
      */
-    override fun getItemPosition(`object`: Any?): Int {
-        return POSITION_NONE
+    override fun getItemPosition(obj: Any?): Int {
+        val view = obj as? LibraryCategoryView ?: return POSITION_NONE
+        val index = categories.indexOfFirst { it.id == view.category.id }
+        return if (index == -1) POSITION_NONE else index
     }
 
 }

app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryCategoryView.kt

@@ -41,7 +41,8 @@ class LibraryCategoryView @JvmOverloads constructor(context: Context, attrs: Att
     /**
      * Category for this view.
      */
-    private lateinit var category: Category
+    lateinit var category: Category
+        private set
 
     /**
      * Recycler view of the list of manga.