convert strechspacers to regular

src/main.py

@@ -85,7 +85,7 @@ class Cast(wx.Frame):
     def show_provider_list(self, _) -> None:
         self.m_sizer.Clear(delete_windows=True)
         self.m_sizer = wx.BoxSizer(wx.VERTICAL)
-        self.m_sizer.AddStretchSpacer()
+        self.m_sizer.AddSpacer(SPACER_HEIGHT * 4)
         closebtn = wx.Button(self.m_panel, -1, label="Close", size=(WIDTH, BTN_HEIGHT))
         closebtn.Bind(wx.EVT_BUTTON, lambda event: self.Destroy())
         self.m_sizer.Add(closebtn)
@@ -107,7 +107,7 @@ class Cast(wx.Frame):
         self.m_selected_provider = self.m_providers[provider_index]
         self.m_sizer.Clear(delete_windows=True)
         self.m_sizer = wx.BoxSizer(wx.VERTICAL)
-        self.m_sizer.AddStretchSpacer()
+        self.m_sizer.AddSpacer(SPACER_HEIGHT * 4)
         bck_callback = lambda event: self.show_provider_list(event)
         self.add_back_button(bck_callback)
         channel_index = 0
@@ -126,7 +126,7 @@ class Cast(wx.Frame):
     def show_video_list(self, _, index=0) -> None:
         self.m_sizer.Clear(delete_windows=True)
         self.m_sizer = wx.BoxSizer(wx.VERTICAL)
-        self.m_sizer.AddStretchSpacer()
+        self.m_sizer.AddSpacer(SPACER_HEIGHT * 4)
         channel = self.m_selected_provider.get_channel_by_index(index)
         if channel.wait():
             with wx.BusyInfo("Please wait, working..."):
@@ -173,7 +173,7 @@ class Cast(wx.Frame):
         """
         self.m_sizer.Clear(delete_windows=True)
         self.m_sizer = wx.BoxSizer(wx.VERTICAL)
-        self.m_sizer.AddStretchSpacer()
+        self.m_sizer.AddSpacer(SPACER_HEIGHT * 4)
         inner_sizer = wx.GridBagSizer()
         self.m_control = wx.media.MediaCtrl(
             self.m_panel,
@@ -231,7 +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()
+        self.m_sizer.AddSpacer(SPACER_HEIGHT * 4)
 
         cancel_btn = wx.Button(self.m_panel, -1, "Cancel", size=(WIDTH, BTN_HEIGHT), style=wx.BU_EXACTFIT)
         cancel_btn.Bind(