When you have a folder the screen sets a scroll region around the folder area and as such the 'Col and 'Line will reflect the location relative this scroll region.
If you are popup menu you can generally just omit the location and the system will position the popup_menu below the control that currently being processed or the current mouse position.
Here is a program that you can use to demo this behaviour.
0010 PRINT 'CS',
0020 BUTTON 10,@(10,10,10,10)="Hit me"
0030 CHECK_BOX 11,@(5,5,30,1)="Click here"
0040 MULTI_LINE 12,@(5,8,30,1),MNU=99
0050 WHILE 1
0060 OBTAIN (0,SIZ=1)'BI',*,'EI'
0070 IF CTL=4 OR EOM=ESC THEN BREAK
0080 POPUP_MENU "-[&File,&Edit]",x