How to make gitk not overwrite my selection?

[Jean-Luc Herren <jlh@gmx.ch>]

Hi list!

In gitk, whenever I select a commit in the tree, the SHA1 field
gets automatically selected, putting its hash into the current
selection for easy pasting into other applications.  I wonder if I
can disable this, because I find it rather annoying; if I do
happen to want to paste the hash somewhere, I can easily double
click the SHA1 field.

This is specially annoying when I select a hash in xterm and then
start gitk to paste it in the SHA1 field.  But immediately after
gitk opens, it preselects the current HEAD, overwriting my
previous selection from xterm.

Generally I think an application should not replace the selection
unless the user explicitely marks something.  Although I can
understand that it can be useful sometimes with gitk.  Therefore
it should maybe be optional.

Thanks,
jlh