Adds a grid-panel in the TabPanel. The panel will be registered in the GuiPanelMng,
so the access to the panel can be done with its name.
The position of the widget manager is set to full area of this panel.
sName - The name, used in
sLabel - to designate the tab for view. A "&" left from a character determines the hot-key
to select the tab.
yGrid - number of units per grid line vertical. It may be 1.
xGrid - number of units per grid line horizontal. It may be 1.
yGrid2 - Number of grid lines vertical per wider ranges for lines
xGrid2 - Number of grid lines horizontal per wider ranges for lines
The named tab should be focused.
TODO which widget should be focused? It may be a first widget in any GralPanelContent?
In SWT it works if any widget in a tab is focused. The the tab is focused then automatically.
It means this method is not necessary. If selectTab is called, the whole tab has the focus
which means it content is visible. That is able to use.