Transparent panel with Umano SlidingUpPanel

I have created a sliding layout using the Umano code: https://github.com/umano/AndroidSlidingUpPanel It works perfectly, but I have one problem. My panel should be partly transparent, so the original view is still visible when it's up. The view background is set properly to #64000000, but it is still completely opaque and nothing can be seen behind it. Here's the code: ``` <com.sothree.slidinguppanel.SlidingUpPanelLayout android:id="@+id/sliding_up_panel" android:layout_height="match_parent" android:layout_width="match_parent"> <ImageView android:layout_height="match_parent" android:layout_width="match_parent" android:scaleType="fitCenter" android:id="@+id/images_gallery_image" /> <RelativeLayout android:layout_width="fill_parent" android:layout_height="match_parent" android:background="#64000000"> <!-- MY STUFF (transparent stuff) --> </RelativeLayout> </com.sothree.slidinguppanel.SlidingUpPanelLayout> ``` I thought maybe the issue is caused by hiding of UI elements underneath the expanded panel, so I tried to play around in the library code, but it doesn't seem to be related. While debugging, I have noticed that hasOpaqueBackground(View v) in line 355 of the library does return false, as expected - but the view still is opaque.