I am missing replace_frame.h from the latest patch.
Edit: Never mind, found it.
Edit 2: gerw, what did you do to get it to complile? I have a great difficulty with header files, such that it produces thousands of errors. Specifically, grund.h, which includes simdepot.h (which, in turn, includes the new gui_convoi_assember.h) complains that the depot_t class is not defined. I have pored over gui_convoi_assember.h for a very long time and not found any syntax errors, so I am very confused.
Edit 3: I have managed to fix the problem by replacing the line, #include "gui/components/gui_convoy_assembler.h in simdepot.h with a forward declaration to gui_convoy_assembler. I am still not quite sure what caused the original problem, but, since this solution is preferable in any event, it seems satisfactory overall.
Edit 4: An interim idea for dealing with the electrics issue: simply have a button in the replace GUI with the label, "show electrics", which is on by default if the current convoy contains electrics, and off by default if it does not.
Edit 5: Another idea would be to suppress the "entered depot" dialogue box when vehicles enter a depot as a result of the vehicle replacer and they are set to leave the depot again automatically. Also, we need help text for the replace window.