Calendar tabs

Hi,

In our application, we did activate the "useSimpleTabs" option in all our TabSet's, with a custom CSS.
I've recently added a Calendar into a screen and noticed that this option could not be applied to the "Day/Week/Month" Tabset, which leads to big style inconsistency in our GUI.

Is there any way to activate this option for this tabset?

Many thanks,
Thomas

PS: Using SGWT-Power 4.1 / SmartClient Version: v9.1p_2014-07-03/PowerEdition Deployment (built 2014-07-03)