How to remove DropHandler from a component?

Vaadin 6 / 7 / 8 Framework UI
1

Hello!
I’m using this:

tree.setDropHandler(getMyDropHandler());

for attaching the handler for my tree component.
It works correctly.

But in a certain point of my program I need to
remove
 the handler
from the component (tree).

Since there is no method like “removeDropHandler()”,
I was wondering how to do that.

I tried this:

tree.setDropHandler(null);

but doesnt seem to work, and I get this error:

java.lang.RuntimeException: java.lang.NullPointerException
	at com.vaadin.terminal.gwt.server.AbstractCommunicationManager.handleVariables(AbstractCommunicationManager.java:1112)
	at com.vaadin.terminal.gwt.server.AbstractCommunicationManager.doHandleUidlRequest(AbstractCommunicationManager.java:590)
	at com.vaadin.terminal.gwt.server.CommunicationManager.handleUidlRequest(CommunicationManager.java:266)
	at com.vaadin.terminal.gwt.server.AbstractApplicationServlet.service(AbstractApplicationServlet.java:476)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
	at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:852)
	at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
	at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
	at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NullPointerException
	at com.vaadin.terminal.gwt.server.DragAndDropService.handleDragRequest(DragAndDropService.java:119)
	at com.vaadin.terminal.gwt.server.DragAndDropService.changeVariables(DragAndDropService.java:73)
	at com.vaadin.terminal.gwt.server.AbstractCommunicationManager.handleVariables(AbstractCommunicationManager.java:1094)
	... 16 more

can you help me to figure out the solution?

thank you

2

For me this sounds like a bug. Could you create a
ticket
 about the issue?