diff --git a/gitk b/gitk
index 269f9b08a0..f1b80ff39a 100755
--- a/gitk
+++ b/gitk
@@ -6972,7 +6972,7 @@ proc doprefs {} {
     pack $top.ntag.b $top.ntag.l -side left
     grid x $top.ntag -sticky w
     label $top.tabstopl -text "tabstop" -font optionfont
-    entry $top.tabstop -width 10 -textvariable tabstop
+    spinbox $top.tabstop -from 1 -to 20 -width 4 -textvariable tabstop
     grid x $top.tabstopl $top.tabstop -sticky w
 
     label $top.cdisp -text "Colors: press to choose"