c-tree assumes resource entries will be locked only for short intervals. This means you should process resource updates without permitting user interactions to occur during the actual update. Do not lock a resource and then request user input. If necessary, adopt a three buffer approach, as described in Multi-User Concepts, to permit a resource update requiring user interaction.
If a file is created with transaction control, (either ctPREIMG or ctTRNLOG has been OR-ed into the file mode at create time), be careful not to include resource updates, (additions, deletions or updates), in long transactions. Locks cannot be released until a transaction commits or aborts.