I've recently updated EE to 2.5.5 and Matrix to 2.5.3, but now one of out in-house addons is broken. The addon is a custom fieldtype designed to be included in a Matrix field, but this now causes the publish page to turn blank. This is the only scenario in which this occurs; Matrix plays nicely with everything else, and our addon doesn't break anything when not included in a Matrix field.
I've tested this with a locally hosted version of EE 2.5.3, and got a PHP error rather than a blank page:
A PHP Error was encountered
Message: Undefined property: Content_publish::$tools_model
Line Number: 271
Fatal error: Call to a member function get_upload_preferences() on a non-object in C:\Program Files\EasyPHP-12.1\www\EE\system\expressionengine\third_party\custom_fieldtype\ft.custom_fieldtype.php on line 271
Anyone know what's going on here?