Lei,
If you are talking about the on screen widgets then you open the [install dir]\server\apps\[app#]\jimu.js\OnScreenWidgetIcon.js file and edit the switchToOpen function like this:
switchToOpen: function(){
this.state = 'opened';
// this.panelManager.closeAllPanelsInGroup(this.widgetConfig.gid);
// array.forEach(this.widgetManager.getOnScreenOffPanelWidgets(), function(widget){
// if(widget.closeable){
// this.widgetManager.closeWidget(widget);
// }
// }, this);
html.addClass(this.domNode, 'jimu-state-selected');