diff --git a/.appveyor.yml b/.appveyor.yml
index 508746db6a..608f8d0fc6 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -1,5 +1,11 @@
 version: "{build}"
 
+branches:
+  except:
+    - /^travis.*$/
+
+clone_depth: 1
+
 os: Visual Studio 2015
 
 platform: 
@@ -10,12 +16,37 @@ configuration:
   - Debug
   - Release
 
+cache:
+  - ci_deps_win_v01.zip
+
+environment:
+  # Update dependencies here: https://github.com/coelckers/gzdoom/releases/tag/ci_deps
+  DEPS_URL: https://github.com/coelckers/gzdoom/releases/download/ci_deps/
+  DEPS_FILENAME: ci_deps_win_v01.zip
+
+install:
+  - if not exist "%DEPS_FILENAME%"
+    appveyor DownloadFile "%DEPS_URL%%DEPS_FILENAME%"
+  - 7z x -y "%DEPS_FILENAME%"
+
 before_build:
-  - cmd: md build
-  - cmd: cd build
-  - cmd: if "%platform%"=="Win32" set CMAKE_GENERATOR_NAME=Visual Studio 14 2015
-  - cmd: if "%platform%"=="x64"   set CMAKE_GENERATOR_NAME=Visual Studio 14 2015 Win64
-  - cmd: cmake -G "%CMAKE_GENERATOR_NAME%" -DCMAKE_BUILD_TYPE=%configuration% ..
+  - md build
+  - cd build
+  - if "%PLATFORM%"=="Win32" set CMAKE_GENERATOR_NAME=Visual Studio 14 2015
+  - if "%PLATFORM%"=="x64"   set CMAKE_GENERATOR_NAME=Visual Studio 14 2015 Win64
+  - set DEPS_INCLUDE_DIR=%APPVEYOR_BUILD_FOLDER%\ci_deps_win\include
+  - set DEPS_LIB_DIR=%APPVEYOR_BUILD_FOLDER%\ci_deps_win\lib\%PLATFORM%
+  - cmake -G "%CMAKE_GENERATOR_NAME%" -T "v140_xp"
+    -DCMAKE_BUILD_TYPE="%CONFIGURATION%"
+    -DFMOD_INCLUDE_DIR="%DEPS_INCLUDE_DIR%"
+    -DFMOD_LIBRARY="%DEPS_LIB_DIR%\fmodex.lib"
+    -DOPENAL_INCLUDE_DIR="%DEPS_INCLUDE_DIR%"
+    -DOPENAL_LIBRARY="%DEPS_LIB_DIR%\OpenAL32.lib"
+    -DMPG123_INCLUDE_DIR="%DEPS_INCLUDE_DIR%"
+    -DMPG123_LIBRARIES="%DEPS_LIB_DIR%\libmpg123-0.lib"
+    -DSNDFILE_INCLUDE_DIR="%DEPS_INCLUDE_DIR%"
+    -DSNDFILE_LIBRARY="%DEPS_LIB_DIR%\libsndfile-1.lib"
+    ..
 
 build:
   project: build\GZDoom.sln
diff --git a/src/d_main.cpp b/src/d_main.cpp
index e5cf881baf..6edb61601e 100644
--- a/src/d_main.cpp
+++ b/src/d_main.cpp
@@ -288,7 +288,7 @@ void D_ProcessEvents (void)
 		if (M_Responder (ev))
 			continue;				// menu ate the event
 		// check events
-		if (E_Responder(ev)) // [ZZ] ZScript ate the event
+		if (ev->type != EV_Mouse && E_Responder(ev)) // [ZZ] ZScript ate the event // update 07.03.17: mouse events are handled directly
 			continue;
 		G_Responder (ev);
 	}
@@ -310,7 +310,7 @@ void D_PostEvent (const event_t *ev)
 		return;
 	}
 	events[eventhead] = *ev;
-	if (ev->type == EV_Mouse && !paused && menuactive == MENU_Off && ConsoleState != c_down && ConsoleState != c_falling && !E_CheckUiProcessors())
+	if (ev->type == EV_Mouse && menuactive == MENU_Off && ConsoleState != c_down && ConsoleState != c_falling && !E_Responder(ev) && !paused)
 	{
 		if (Button_Mlook.bDown || freelook)
 		{
diff --git a/src/events.cpp b/src/events.cpp
index 5faee810ac..d0d8050cca 100755
--- a/src/events.cpp
+++ b/src/events.cpp
@@ -410,15 +410,21 @@ void E_PlayerDisconnected(int num)
 		handler->PlayerDisconnected(num);
 }
 
-bool E_Responder(event_t* ev)
+bool E_Responder(const event_t* ev)
 {
+	bool uiProcessorsFound = false;
+
 	if (ev->type == EV_GUI_Event)
 	{
 		// iterate handlers back to front by order, and give them this event.
 		for (DStaticEventHandler* handler = E_LastEventHandler; handler; handler = handler->prev)
 		{
-			if (handler->IsUiProcessor && handler->UiProcess(ev))
-				return true; // event was processed
+			if (handler->IsUiProcessor)
+			{
+				uiProcessorsFound = true;
+				if (handler->UiProcess(ev))
+					return true; // event was processed
+			}
 		}
 	}
 	else
@@ -426,12 +432,14 @@ bool E_Responder(event_t* ev)
 		// not sure if we want to handle device changes, but whatevs.
 		for (DStaticEventHandler* handler = E_LastEventHandler; handler; handler = handler->prev)
 		{
+			if (handler->IsUiProcessor)
+				uiProcessorsFound = true;
 			if (handler->InputProcess(ev))
 				return true; // event was processed
 		}
 	}
 
-	return false;
+	return (uiProcessorsFound && (ev->type == EV_Mouse)); // mouse events are eaten by the event system if there are any uiprocessors.
 }
 
 void E_Console(int player, FString name, int arg1, int arg2, int arg3, bool manual)
@@ -939,7 +947,7 @@ void DStaticEventHandler::PlayerDisconnected(int num)
 	}
 }
 
-FUiEvent::FUiEvent(event_t *ev)
+FUiEvent::FUiEvent(const event_t *ev)
 {
 	Type = (EGUIEvent)ev->subtype;
 	KeyChar = 0;
@@ -979,7 +987,7 @@ FUiEvent::FUiEvent(event_t *ev)
 	}
 }
 
-bool DStaticEventHandler::UiProcess(event_t* ev)
+bool DStaticEventHandler::UiProcess(const event_t* ev)
 {
 	IFVIRTUAL(DStaticEventHandler, UiProcess)
 	{
@@ -998,7 +1006,7 @@ bool DStaticEventHandler::UiProcess(event_t* ev)
 	return false;
 }
 
-FInputEvent::FInputEvent(event_t *ev)
+FInputEvent::FInputEvent(const event_t *ev)
 {
 	Type = (EGenericEvent)ev->type;
 	// we don't want the modders to remember what weird fields mean what for what events.
@@ -1025,7 +1033,7 @@ FInputEvent::FInputEvent(event_t *ev)
 	}
 }
 
-bool DStaticEventHandler::InputProcess(event_t* ev)
+bool DStaticEventHandler::InputProcess(const event_t* ev)
 {
 	IFVIRTUAL(DStaticEventHandler, InputProcess)
 	{
diff --git a/src/events.h b/src/events.h
index 6a84da3f64..292030333e 100755
--- a/src/events.h
+++ b/src/events.h
@@ -56,7 +56,7 @@ void E_PlayerDied(int num);
 // this executes when a player leaves the game
 void E_PlayerDisconnected(int num);
 // this executes on events.
-bool E_Responder(event_t* ev); // splits events into InputProcess and UiProcess
+bool E_Responder(const event_t* ev); // splits events into InputProcess and UiProcess
 // this executes on console/net events.
 void E_Console(int player, FString name, int arg1, int arg2, int arg3, bool manual);
 
@@ -148,8 +148,8 @@ public:
 	void PlayerDisconnected(int num);
 
 	// return true if handled.
-	bool InputProcess(event_t* ev);
-	bool UiProcess(event_t* ev);
+	bool InputProcess(const event_t* ev);
+	bool UiProcess(const event_t* ev);
 	
 	// 
 	void ConsoleProcess(int player, FString name, int arg1, int arg2, int arg3, bool manual);
@@ -215,7 +215,7 @@ struct FUiEvent
 	bool IsCtrl;
 	bool IsAlt;
 
-	FUiEvent(event_t *ev);
+	FUiEvent(const event_t *ev);
 };
 
 struct FInputEvent
@@ -230,7 +230,7 @@ struct FInputEvent
 	int MouseX;
 	int MouseY;
 
-	FInputEvent(event_t *ev);
+	FInputEvent(const event_t *ev);
 };
 
 struct FConsoleEvent