fix some switchable-button tooltip problems

collects/mrlib/switchable-button.rkt

@@ -89,6 +89,7 @@
       (unless show?
         (set! in? #f)
         (set! down? #f)
+                (update-float #f)
         (refresh))
       (super on-superwindow-show show?))
     
@@ -105,6 +106,7 @@
          (refresh)
          (when (and in?
                     (not disabled?))
+           (update-float #f)
            (callback this))]
         [(send evt entering?)
          (set! in? #t)
@@ -145,7 +147,7 @@
            (unless (and float-window
                         (equal? new-value? (send float-window is-shown?)))
              (cond
-               [in?
+               [new-value?
                 (unless float-window
                   (set! float-window (new frame% 
                                           [label ""]
@@ -186,8 +188,8 @@
                     (<= 0 (send evt get-y) ch))])
           (unless (equal? new-in? in?)
             (set! in? new-in?)
-            (update-float in?)
-            (refresh)))))
+            (refresh))
+          (update-float new-in?))))
     
     (define/override (on-paint)
       (let ([dc (get-dc)])