To specify some global options, choose Settings|Global Options. You can set the following:
If you want to use a different version of gdb, you can specify it under How to invoke GDB. The default command is gdb --fullname --nx. Be sure to also specify these options if you change the gdb executable. If you leave them away, KDbg will not work. If you messed up the entry, you can clear it to revert to the default setting.
If you want to use a different terminal program to show the output of the program, specify it under Terminal for program output. The default setting is xterm -name kdbgio -title %T -e sh -c %C. In this entry, %T will be replaced by a title string, %C will be replaced by a Bourne shell script that loops infinitely so that the terminal window doesn't close. (No, it doesn't use CPU, it calls sleep 3600 in a loop :) An alternative for this setting could be konsole --name kdbgio --caption %T -e sh -c %C.
You can specify whether the KDbg window shall move itself into the foreground as soon as the program being debugged stops (at a breakpoint or due to a signal). The KDbg window is not activated, however (at least under KWM, the KDE window manager). Some users may feel that this behavior is intrusive, so this option is off by default.
If this option is on, KDbg will also retreat itself into the background when the program is continued by any command, but it does so only after a timeout that can be specified. This avoids that the debugger window flashes back and forth each time you click any of the Step commands.
You can specify wildcards for source files and header files, which are used in the file dialog of the File|Open Source command.