You can use global fields to accept user selection then script trigger OnObjectModify to run your script. It can include script parameter if you wish as well. :-)
I created a global field and placed it on a layout below the related icon. I created a script to accept the value of the new field as a parameter. I made the OnObjectModify trigger of the field call the new script. I created a value list to contain the values to appear in the popup menu. Everything works well except for 2 problems:
1. Because the new global field is configured as a pop-up menu, it appears to have a drop shadow effect and I don't know how to prevent that.
2. The OnObjectModify script trigger causes the script to execute but the value it passes to the parameter is the previous value of the feld, not the value just selected from the popup menu
OK I solved the problem of the parameter being sent to the script being the previous value of the new field rather than the selection from the popup menu. Instead I changed the OnObjectModify script trigger so that it didn't send any parameter to the script. I also modified the script to first commit record then just use the value of the global field to determine the action to be taken.
Now I just have the problem of the drop shadow around the field configured as a popup menu.
I solved that problem also. I just hid the field behind an opaque rectangle object.
Thanks very much.