git-gui: Only allow Refresh in diff context menu when we have a diff.

There is no reason to attempt refreshing an empty diff viewer, so
the Refresh option of our diff context menu should be disabled when
there is no diff currently shown.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

diff --git a/git-gui.sh b/git-gui.sh
index 79f980c470707ca74c95503df9c334541c66200e..b9e3d563e2bef9eb642aa0e3e8fc2b9892b3873a 100755 (executable)
--- a/git-gui.sh
+++ b/git-gui.sh
@@ -4261,6 +4261,7 @@ $ctxm add command \
        -label {Refresh} \
        -font font_ui \
        -command reshow_diff
+lappend diff_actions [list $ctxm entryconf [$ctxm index last] -state]
 $ctxm add command \
        -label {Copy} \
        -font font_ui \