BadWindowToken Exception when showing indicator when slider is inside a PopupWindow

I have a DiscreteSeekBar inside a view inside a android.widget.PopupWindow.
and I get an exception when DiscreteSeekBar tries to show indicatior.

android.view.WindowManager$BadTokenException: Unable to add window -- token android.view.ViewRootImpl$W@11502996 is not valid; is your activity running?
at android.view.ViewRootImpl.setView(ViewRootImpl.java:562)
at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:282)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:85)
at org.adw.library.widgets.discreteseekbar.internal.PopupIndicator.invokePopup(PopupIndicator.java:166)
at org.adw.library.widgets.discreteseekbar.internal.PopupIndicator.showIndicator(PopupIndicator.java:111)
at org.adw.library.widgets.discreteseekbar.DiscreteSeekBar.showFloater(DiscreteSeekBar.java:971)
at org.adw.library.widgets.discreteseekbar.DiscreteSeekBar.access$100(DiscreteSeekBar.java:52)
at org.adw.library.widgets.discreteseekbar.DiscreteSeekBar$2.run(DiscreteSeekBar.java:964)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5294)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:904)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:699)