--- rpl/modules/motif/XtAppMainLoop.rplc	2017/07/06 10:18:04	1.2
+++ rpl/modules/motif/XtAppMainLoop.rplc	2017/07/17 21:35:32	1.3
@@ -15,11 +15,14 @@ declareExternalFunction(XtAppMainLoop)
 			pullFromStack(appObject, external);
 			returnOnError(freeObject(appObject));
 
-			if (subType(appObject) ne APPCONTEXT) then
+			ifIsExternal(appObject, APPCONTEXT) then
+			orElse
 				executionError("Type mismatch");
 				returnOnError(freeObject(appObject));
 			endIf
 
+			intrinsic(pshcntxt);
+
 			doUntil
 				if (XtAppPending(target((sXtAppContext *)
 						objectContainer(appObject)).context) ne 0) then
@@ -45,6 +48,8 @@ declareExternalFunction(XtAppMainLoop)
 					(stopRequest eq -1) or
 					(exitMainLoop ne 0))
 
+			intrinsic(pulcntxt);
+
 			XtDestroyApplicationContext(target((sXtAppContext *)
 					objectContainer(appObject)).context);
 		orElse