Initially, when no item is selected (i.e. both rule_name and name are "None") same_name toggle is checked in tech tab, but not in other tabs. I think it should (as it should be the default).
In the code, the difference between techs and at least terrains tab seems to be that techs call update_tech_info() in the end of the constructor, while terrains does not call update_terrain_info(). Those update_*_info() methods set same_name toggled in case of no-item-selected. There might be other functionality in update_*_info() that should be executed in the constructor.
Initially, when no item is selected (i.e. both rule_name and name are "None") same_name toggle is checked in tech tab, but not in other tabs. I think it should (as it should be the default).
In the code, the difference between techs and at least terrains tab seems to be that techs call update_tech_info() in the end of the constructor, while terrains does not call update_terrain_info(). Those update_*_info() methods set same_name toggled in case of no-item-selected. There might be other functionality in update_*_info() that should be executed in the constructor.