Crash in editor


I am trying to use some ides form ShooterGame demo.
To show my Welcome view, I am using that code to load my Welcome view level:

GetEngine()->Browse(*WorldContext, URL, Error);

But with no luck. I am launching game in editor. The assert showing in function:

UEditorEngine::Tick( float DeltaSeconds, bool bIdleMode )

in the string

check( CurrentGWorld != PlayWorld || bIsSimulatingInEditor );

where CurrentGWorld is equal to PlayWorld and bIsSimulatingInEditor is FALSE;

How can I pass that check? Have I missed something?
Please advice