Xbench approach is to be a browser rather than an editor, and outsource all editing tasks to the native editor via Edit Source (Ctrl+E). So what we try instead is to make Edit Source as smooth and seamless as possible.
The rationale for this approach is to ensure data integrity at all times by making that only the native editor is authorized to modify data.
Most of the CAT formats supported by Xbench are proprietary and undocumented. For example, sdlxliff or mqxliff are proprietary formats, built on the XLIFF standard if you wish, but still fully proprietary.
We could probably write an editor that works well today for the proprietary formats we support. But since the formats would be proprietary, the format owner could make a slight change in it any time in the future that breaks compatibility. This means that our editor that writes perfectly correct data today could write corrupt data tomorrow.
The current design decision (be a browser that outsources all editing functions to the native editor), makes not possible this kind of global change functionality, although we recognize that it could bring a lot of value and might implement it in the future for well documented non-proprietary formats.