This is the third report in 2 days that I have seen of this.
I have recommended that this behavior change in Windows, FMP 12 be reported in Report an Issue as a possible bug, but have not seen such a report appear just yet.
Thanks. I have added bug report and will post any response here or workaround for others.
I also have this issue and it is quite serious.
There is no way to navigate large popup menus in Windows. I did a scalability test and loaded a popup menu with thousands of records and although the popup menu displays them fine the only way we can scroll is one entry at a time using the little triangle icons at the top and bottom, page up/down and type ahead don't work at all!
This is totally impractical for any decent size database and as bug it should at the top of the list! I have just upgraded to 12.0v3 and it still has the problem.
I have since solved this using the details from this previous link http://www.4shared.com/file/plr_jbkk/EnhancedValueSelection.html
Basically this shows a few ways of doing it, so dont get too bogged down.
I implemented a vl_search_fields table with global storage values for each list
I added this field to the layout and made it a dropdown list
I made a new valuelist for the different values (normally using a new table containing a key value pair)
I then used the script form the link as a guide as to how to find the key from the value - you basically go to table layout and do a find - you then set the key field to what you actually want
A bit fiddly with all the lists I have, you have to set script triggers on entry and exit to clear and refresh th right values etc, but I cracked it eventually and it works for both mac and windows. Wont work for the web though as it doesnt use script triggers, but then type ahead works fine for the web anyhow and will have different layouts!
Hope that helps and thanks to the author of the original script.
This demo file illustrates a similar "type ahead" method but more simply:
FileMaker 12 users: https://dl.dropbox.com/u/78737945/SimpleNameLookupDemo.fmp12
Pre FileMaker 12 Users: https://dl.dropbox.com/u/78737945/SimpleNameLookupDemo.fp7
Perhap you should rethink that Pop-Up Menu user interface. Most word processor did when the Font Selection became unwieldy. Most went to a Inspector type selection. Inspectors are pretty much a portal.
Thanks for the examples and advice, very useful. I will try and move to a portal type method in the future. In the meantime I have a simple but clunky solution. I use the popup menu simply to display the second field in the value list and a drop down to do the actual selecting. I prevent the user from clicking on the popup menu thus forcing them to use the drop down control, I cant seem to remove the down arrow from the popup control so it will just have to stay!
Instead of the pop up menu, put the name field from the related table on your layout next to the drop down list. Now you have no drop down arrow.
Another trick is to put the name field on top of the drop down list. Give the name field an opaque fill color and use behavior settings in the inspector to deny access when in browse mode. When the user clicks on the name field from the related table, the hidden drop down list pops to the front and deploys. After selecting a value, the drop down disappears back behind the name field and the name field updates to display the selected name.
Of course now you will want that drop down arrow, but you can select a drop down list format for your "no access" name field just to give it that arrow if you wish...