def _new_tab(self):
"""Spawn a new tab page"""
layout = QGridLayout()
layout.setSpacing(1)
layout.setContentsMargins(0, 0, 0, 0)
widget = QMdiArea()
widget.setLayout(layout)
tab = self.tab_bar
tab.addTab(widget, str(tab.count()+1))
tab.setCurrentWidget(widget)
