Fixed wrong heartbeat interval causing Vaadin "Communication Error" in the sitemap editor. 
Fixed wrong heartbeat interval causing Vaadin "Communication Error" in
the sitemap editor. 
alkacon/opencms-core,ggiudetti/opencms-core,alkacon/opencms-core,alkacon/opencms-core,ggiudetti/opencms-core,gallardo/opencms-core,ggiudetti/opencms-core,ggiudetti/opencms-core,gallardo/opencms-core,gallardo/opencms-core,alkacon/opencms-core,gallardo/opencms-core