There isn't an automatic way to do that, however, you could construct your application to add additional rows, breaking on every 5 tabs.
Here is a hardwired illustration of setting up the rows. Your program would just have to programatically build the structure
Names Default To Here( 1 );
New Window( "Example",
Tab Box(
Tab Page Box(
"Row One",
Tab Box(
Tab Page Box( "Alpha", Popup Box( {"x", ex = 1, "y", ex = 2} ) ),
Tab Page Box( "Beta", Popup Box( {"x", ex = 1, "y", ex = 2} ) ),
Tab Page Box( "Gamma", Popup Box( {"x", ex = 1, "y", ex = 2} ) )
)
),
Tab Page Box(
"Row Two",
Tab Box(
Tab Page Box( "Alpha2", Popup Box( {"x", ex = 1, "y", ex = 2} ) ),
Tab Page Box( "Beta2", Popup Box( {"x", ex = 1, "y", ex = 2} ) ),
Tab Page Box( "Gamma2", Popup Box( {"x", ex = 1, "y", ex = 2} ) )
)
),
Tab Page Box(
"Row Three",
Tab Box(
Tab Page Box( "Alpha3", Popup Box( {"x", ex = 1, "y", ex = 2} ) ),
Tab Page Box( "Beta3", Popup Box( {"x", ex = 1, "y", ex = 2} ) ),
Tab Page Box( "Gamma3", Popup Box( {"x", ex = 1, "y", ex = 2} ) )
)
)
)
);
Jim