add a GUI interface to toggle the x selection mode

closes PR 15365

gui-lib/framework/private/main.rkt

@@ -25,6 +25,12 @@
 
 (application-preferences-handler (λ () (preferences:show-dialog)))
 
+(preferences:set-default 'framework:editor-x-selection-mode #t boolean?)
+(when (equal? (system-type) 'unix)
+  (preferences:add-callback
+   'framework:editor-x-selection-mode
+   (λ (p v) (editor-set-x-selection-mode v))))
+
 (preferences:set-default 'framework:ascii-art-enlarge #f boolean?)
 
 (preferences:set-default 'framework:color-scheme 'classic symbol?)

gui-lib/framework/private/preferences.rkt

@@ -512,6 +512,11 @@ the state transitions / contracts are:
                                (string-constant maximum-char-width-guide-pref-check-box)
                                (λ (n) (and (exact-integer? n) (>= n 2))))
 
+                   (when (equal? (system-type) 'unix)
+                     (add-check editor-panel
+                                'framework:editor-x-selection-mode
+                                (string-constant editor-x-selection-mode)))
+                   
                    (editor-panel-procs editor-panel))))])
       (add-editor-checkbox-panel)))
 

gui-lib/info.rkt

@@ -12,7 +12,7 @@
                "pict-lib"
                "scheme-lib"
                "scribble-lib"
-               ["string-constants-lib" #:version "1.9"]
+               ["string-constants-lib" #:version "1.14"]
                "option-contract-lib"
                "2d-lib"
                "compatibility-lib"