Put player in another sizer

src/main.py

@@ -172,7 +172,9 @@ class Cast(wx.Frame):
         :param uri str: the link to the video stream
         """
         self.m_sizer.Clear(delete_windows=True)
-        self.m_sizer = wx.GridBagSizer()
+        self.m_sizer = wx.BoxSizer(wx.VERTICAL)
+        self.m_sizer.AddStretchSpacer()
+        inner_sizer = wx.GridBagSizer()
         self.m_control = wx.media.MediaCtrl(
             self.m_panel,
         #    size=(WIDTH, HEIGHT/2),
@@ -189,11 +191,11 @@ class Cast(wx.Frame):
             lambda event, index=provider_index: self.show_video_list(event, index),
         )
 
-        self.m_sizer.Add(self.m_control, (0, 0))
-        self.m_sizer.SetItemSpan(0, (0, 6))
-        self.m_sizer.Add(play_button, (1, 1))
-        self.m_sizer.Add(pause_button, (1, 2))
-        self.m_sizer.Add(back_button, (1, 3))
+        inner_sizer.Add(self.m_control, (0, 0))
+        inner_sizer.SetItemSpan(0, (0, 6))
+        inner_sizer.Add(play_button, (1, 1))
+        inner_sizer.Add(pause_button, (1, 2))
+        inner_sizer.Add(back_button, (1, 3))
 
         if not self.m_chromecast_thr.is_alive() and not self.m_selected_chromecast:
             chromecast_button = wx.Button(self.m_panel, -1, "Cast")
@@ -203,7 +205,8 @@ class Cast(wx.Frame):
                     event, muri, index
                 ),
             )
-            self.m_sizer.Add(chromecast_button, (2, 2))
+            inner_sizer.Add(chromecast_button, (2, 2))
+        self.m_sizer.Add(inner_sizer)
 
         if self.m_selected_chromecast:
             self.Bind(
@@ -228,6 +231,7 @@ class Cast(wx.Frame):
     def select_chromecast(self, _, uri, provider_index):
         self.m_sizer.Clear(delete_windows=True)
         self.m_sizer = wx.BoxSizer(wx.VERTICAL)
+        self.m_sizer.AddStretchSpacer()
 
         cancel_btn = wx.Button(self.m_panel, -1, "Cancel", size=(WIDTH, BTN_HEIGHT), style=wx.BU_EXACTFIT)
         cancel_btn.Bind(