java.lang.IllegalStateException: An extension can not be set to extend a new target after getting detached from the previous.
at com.vaadin.server.AbstractExtension.setParent(AbstractExtension.java:88)
at com.vaadin.server.AbstractClientConnector.addExtension(AbstractClientConnector.java:610)
at com.vaadin.server.AbstractExtension.extend(AbstractExtension.java:77)
at com.haulmont.cuba.web.widgets.CubaTimer.extend(CubaTimer.java:43)
at com.haulmont.cuba.web.AppUI.addTimer(AppUI.java:710)
at com.haulmont.cuba.web.gui.components.WebTimer.attachTimerToUi(WebTimer.java:137)
at com.haulmont.cuba.web.gui.components.WebTimer$1.attach(WebTimer.java:128)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.vaadin.event.ListenerMethod.receiveEvent(ListenerMethod.java:496)
at com.vaadin.event.EventRouter.fireEvent(EventRouter.java:273)
at com.vaadin.event.EventRouter.fireEvent(EventRouter.java:237)
at com.vaadin.server.AbstractClientConnector.fireEvent(AbstractClientConnector.java:1041)
at com.vaadin.server.AbstractClientConnector.attach(AbstractClientConnector.java:646)
at com.vaadin.ui.AbstractComponent.attach(AbstractComponent.java:670)
at com.vaadin.ui.AbstractComponent.setParent(AbstractComponent.java:571)
at com.vaadin.ui.AbstractComponentContainer.addComponent(AbstractComponentContainer.java:178)
at com.vaadin.ui.CssLayout.addComponent(CssLayout.java:121)
at com.haulmont.cuba.web.sys.WebScreens.removeThisTabWindow(WebScreens.java:689)
at com.haulmont.cuba.web.sys.WebScreens.remove(WebScreens.java:631)
at com.haulmont.cuba.gui.screen.Screen.close(Screen.java:340)
at com.joker.jokerapp.web.main.OrderScreen.onSendAndCloseBtnClick(OrderScreen.java:1369)
at com.haulmont.bali.events.EventHub.publish(EventHub.java:170)
at com.haulmont.cuba.web.gui.components.WebAbstractComponent.publish(WebAbstractComponent.java:92)
at com.haulmont.cuba.web.gui.components.WebButton.buttonClicked(WebButton.java:65)
at com.haulmont.cuba.web.widgets.CubaButton.fireClick(CubaButton.java:76)
at com.vaadin.ui.Button$1.click(Button.java:57)
It seems something related to Timer, in fact if I remove the timer from the caller screen the error disappear. It start to give me this error few days ago, making apparently no changes to the code.
Could you please prepare a small example where we can reproduce the issue? Without technical details (such as framework version) and working example it is nearly impossible to say what is going on.