Custom PHP file not being executed, but template for the same is?

[DaveFF]

We have some activity types we want to merge or phase out, and some that are only meant to be created automatically by webforms or parts of our custom code. I've been trying to customise CRM_Activity_Form_ActivityLinks to hide the ability to add new activities of these types.

Doing this in custom PHP (would be sites/default/civicrm_custom_php/CRM/Activity/Form/ActivityLinks.php on our system) doesn't work for me- adding a watchdog at the start of the commonBuildQuickForm function reveals that the custom file isn't even being executed. (Have cleared cache, checked for syntax errors etc.)

Taking the corresponding template (sites/default/civicrm_custom_templates/CRM/Activity/Form/ActivityLinks.tpl) and doing a jQuery solution instead works fine.

Can certain core code not be overridden by custom PHP?

[Michael McAndrew]

They can all be.  Do you have other files that are being overridden OK?

If so, maybe there are some obvious typos, differences in file permissions between the two.

If not, are you sure that the custom php directory is correctly defined, etc.

[Hershel]

If not, are you sure that the custom php directory is correctly defined, etc.

Yes, test this first with another custom file, to assure that it works.

[DaveFF]

Never mind, we went with the jQuery version in the end but when I tried again it worked. Thanks for your input.