PowerBuilder - Control-Tab Does Not Increment Tabpage

Issue : One of my coworkers discovered that sometimes << Control-Tab>> didn't work to increment a tabpage to the next tabpage.

Solution : 

uo_search_ancestor          uo_test[]
string                      ls_object[]

ls_object[1] = "uo_search_test"

// tab_1.OpenTab(uo_test[1],0)             // Doesn't work

tab_1.OpenTab(uo_test[1],ls_object[1],0)   // Works