Fix inventory scrollbar's drag state after mouse release (#1666)

src/main/java/appeng/client/gui/AEBaseGui.java

@@ -572,6 +572,14 @@ public abstract class AEBaseGui extends GuiContainer implements IGuiTooltipHandl
         super.mouseClickMove(x, y, c, d);
     }
 
+    @Override
+    protected void mouseMovedOrUp(final int mouseX, final int mouseY, final int state) {
+        if (state >= 0 && this.getScrollBar() != null) {
+            this.getScrollBar().release();
+        }
+        super.mouseMovedOrUp(mouseX, mouseY, state);
+    }
+
     @Override
     protected void handleMouseClick(final Slot slot, final int slotIdx, final int clickedButton, final int clickType) {
         if (clickType == 0 && this.draggedSlots.add(slot)) {

src/main/java/appeng/client/gui/widgets/GuiScrollbar.java

@@ -157,6 +157,10 @@ public class GuiScrollbar implements IScrollSource {
         }
     }
 
+    public void release() {
+        this.isLatestClickOnScrollbar = false;
+    }
+
     public void wheel(int delta) {
         delta = Math.max(Math.min(-delta, 1), -1);
         this.currentScroll += delta * this.pageSize;