If I were you, i would “completely remove” all standard Ubuntu’s ROOT packages and install a new ROOT version according to my “prescription”.
What concerns “default GUI actions”, they are defined in the “root.mimes” file, residing either in the “–etcdir=…” subdirectory (defaults to “/etc/root”) or in the “${ROOTSYS}/etc” subdirectory, which depends on how ROOT was built. Try:
root-config --etcdir/root.mimes
Note: you do not need to modify this system-wide “root.mimes” file, you can simply create your own (copy the original file and then modify it as you like):
$(HOME)/.root.mimes
I believe you have an “/etc/root” subdirectory coming from the standard Ubuntu’s ROOT 5.18.00 (files in there may interfere with your new ROOT installation): http://packages.ubuntu.com/lucid/all/root-system-common/filelist
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