replace scuffed ui fullscreen method

Author: timothywashburn

src/gui.py

@@ -15,7 +15,7 @@ def __init__(self, *args, **kwargs):
 
         self.title("Check-In")
         self.geometry("1280x720")
-        self.after(10000, lambda: self.attributes("-fullscreen", True))
+        self.bind("<Map>", self._on_map)
 
         # Single shared canvas — background is always painted here, never redrawn
         self.canvas = tk.Canvas(
@@ -81,6 +81,10 @@ def __init__(self, *args, **kwargs):
 
         self.show_frame(MainPage)
 
+    def _on_map(self, event):
+        self.unbind("<Map>")
+        self.attributes("-fullscreen", True)
+
     def timeout_fn(self, curr_uuid):
         from screens.MainPage import MainPage
         if curr_uuid == self.frame_uuid: