function _showPanelsIfRequired() {
        var panelIDs = _previouslyOpenPanelIDs;
        panelIDs.forEach(function (panelID) {
            var panel = WorkspaceManager.getPanelForID(panelID);
            if (panel) {
                panel.show();
            }
        });
        _previouslyOpenPanelIDs = [];
    }
show all open panels that was previously hidden by _hidePanelsIfRequired()