Disable pausing on ScreenGameplaySyncMachine.

Docs/Changelog_sm5.txt

@@ -12,7 +12,7 @@ ________________________________________________________________________________
 
 2016/01/14
 ----------
-* [Gameplay] Added pause menu to default theme.  Activated by pressing Start,
+* [Gameplay] Added pause menu to default theme.  Activated by pressing
   Select, or Back twice without pressing something else.  Has options for
   restarting or forfeiting the current song in normal play.  Course mode has
   options for skipping the current song or ending the course or forfeiting.

Themes/default/Graphics/pause_menu.lua

@@ -1,7 +1,7 @@
 gameplay_pause_count= 0
 course_stopped_by_pause_menu= false
 
-local pause_buttons= {Start= true, Select= true, Back= true}
+local pause_buttons= {Start= false, Select= true, Back= true}
 local pause_double_tap_time= 1
 local tap_debounce_time= .1
 local pause_press_times= {}
@@ -161,6 +161,7 @@ local function input(event)
 	local button= event.GameButton
 	if not button then return end
 	if event.type == "InputEventType_Release" then return end
+	if screen_gameplay:GetName() == "ScreenGameplaySyncMachine" then return end
 	local is_paused= screen_gameplay:IsPaused()
 	if is_paused then
 		if menu_is_showing[pn] then