Step to create popup for custom toolbar button:

New a ogs file like custom.ogs with below code, in Customize dialog, select one button and click Settings… button, in Button Settings dialog, set File Name as custom.ogs, set Main as Section Name, set :2 in LabTalk Variable to toogle.

switch (%1)
{
	case 0:
		ty -b 1st button; 
		break;
	case 1:
		ty -b 2nd button; 
		break;
}