Fix [3c2a3a988f]: ttk entry-2.1.1 fails on Ubuntu 22.04 or xvfb.

tests/ttk/entry.test

@@ -7,9 +7,6 @@ package require tcltest 2.2
 namespace import -force tcltest::*
 loadTestedCommands
 
-testConstraint failsOnUbuntu [expr {![info exists ::env(CI)] || ![string match Linux $::tcl_platform(os)]}]
-testConstraint failsOnXQuarz [expr {$tcl_platform(os) ne "Darwin" || [tk windowingsystem] ne "x11" }]
-
 variable scrollInfo
 proc scroll args {
     global scrollInfo
@@ -84,14 +81,15 @@ test entry-2.1 "Create entry before scrollbar" -body {
 	-expand false -fill x
 }  -cleanup {destroy .te .tsb}
 
-test entry-2.1.1 "Create entry before scrollbar - scrollbar catches up" -constraints {failsOnUbuntu failsOnXQuarz} -body {
+test entry-2.1.1 "Create entry before scrollbar - scrollbar catches up" -body {
     pack [ttk::entry .te -xscrollcommand [list .tsb set]] \
-	-expand true -fill both
+	    -expand true -fill both
     .te insert end [string repeat "abc" 50]
     catch {update} ; # error triggers because the -xscrollcommand callback
                      # errors out: invalid command name ".tsb"
+    focus -force .te ; # needed on some systems such as Ubuntu (see ticket [3c2a3a988f])
     pack [ttk::scrollbar .tsb -orient horizontal -command [list .te xview]] \
-	-expand false -fill x
+	    -expand false -fill x
     update ; # no error
     set res [expr [lindex [.tsb get] 1] < 1] ; # scrollbar did update
 } -result 1 -cleanup {destroy .te .tsb}