1) Added MattKing's code for supporting the middle mouse button in [Rainmeter] and [MeasureName].

MiddleMouseUpAction | MiddleMouseDownAction

2) Updated the manual entries for the middle mouse functionality

3) Added  spx268's code to fix a problem with BUTTON and dynamic variables addressed in:

http://code.google.com/p/rainmeter/issues/detail?id=108

Library/Meter.cpp

@@ -264,8 +264,10 @@ void CMeter::ReadConfig(const WCHAR* section)
 
 	m_RightMouseDownAction = parser.ReadString(section, L"RightMouseDownAction", L"");
 	m_LeftMouseDownAction = parser.ReadString(section, L"LeftMouseDownAction", L"");
+	m_MiddleMouseDownAction = parser.ReadString(section, L"MiddleMouseDownAction", L"");
 	m_RightMouseUpAction = parser.ReadString(section, L"RightMouseUpAction", L"");
 	m_LeftMouseUpAction = parser.ReadString(section, L"LeftMouseUpAction", L"");
+	m_MiddleMouseUpAction = parser.ReadString(section, L"MiddleMouseUpAction", L"");
 	m_MouseOverAction = parser.ReadString(section, L"MouseOverAction", L"");
 	m_MouseLeaveAction = parser.ReadString(section, L"MouseLeaveAction", L"");
 

Library/Meter.h

@@ -54,6 +54,8 @@ public:
 	std::wstring& GetRightMouseUpAction() { return m_RightMouseUpAction; };
 	std::wstring& GetLeftMouseDownAction() { return m_LeftMouseDownAction; };
 	std::wstring& GetLeftMouseUpAction() { return m_LeftMouseUpAction; };
+	std::wstring& GetMiddleMouseDownAction() { return m_MiddleMouseDownAction; };
+	std::wstring& GetMiddleMouseUpAction() { return m_MiddleMouseUpAction; };
 	std::wstring& GetMouseOverAction() { return m_MouseOverAction; };
 	std::wstring& GetMouseLeaveAction() { return m_MouseLeaveAction; };
 
@@ -111,6 +113,8 @@ protected:
 	std::wstring m_RightMouseUpAction;
 	std::wstring m_LeftMouseDownAction;
 	std::wstring m_LeftMouseUpAction;
+	std::wstring m_MiddleMouseDownAction;
+	std::wstring m_MiddleMouseUpAction;
 	std::wstring m_MouseOverAction;
 	std::wstring m_MouseLeaveAction;
 

Library/MeterImage.cpp

@@ -37,6 +37,7 @@ using namespace Gdiplus;
 CMeterImage::CMeterImage(CMeterWindow* meterWindow) : CMeter(meterWindow)
 {
 	m_Bitmap = NULL;
+	m_NeedsUpdate = false;
 	m_WidthDefined = false;
 	m_HeightDefined = false;
 	m_PreserveAspectRatio = false;
@@ -71,7 +72,7 @@ void CMeterImage::Initialize()
 {
 	CMeter::Initialize();
 
-	LoadImage(true);
+	if (!m_DynamicVariables) LoadImage(true);
 }
 
 /*
@@ -197,8 +198,6 @@ void CMeterImage::ReadConfig(const WCHAR* section)
 
 	CConfigParser& parser = m_MeterWindow->GetParser();
 
-	m_ImageName = parser.ReadString(section, L"ImageName", L"");
-	
 	m_Path = parser.ReadString(section, L"Path", L"");
 	if (!m_Path.empty())
 	{
@@ -207,7 +206,19 @@ void CMeterImage::ReadConfig(const WCHAR* section)
 			m_Path += L"\\";
 		}
 	}
-	m_ImageName = m_MeterWindow->MakePathAbsolute(m_Path + m_ImageName);
+
+	if (!m_Measure)
+	{
+		std::wstring oldImageName = m_ImageName;
+
+		m_ImageName = parser.ReadString(section, L"ImageName", L"");
+		m_ImageName = m_MeterWindow->MakePathAbsolute(m_Path + m_ImageName);
+
+		if (m_DynamicVariables)
+		{
+			m_NeedsUpdate = (oldImageName != m_ImageName);
+		}
+	}
 
 	m_PreserveAspectRatio = 0!=parser.ReadInt(section, L"PreserveAspectRatio", 0);
 
@@ -229,24 +240,31 @@ void CMeterImage::ReadConfig(const WCHAR* section)
 */
 bool CMeterImage::Update()
 {
-	if (CMeter::Update() && m_Measure)
+	if (CMeter::Update())
 	{
-		std::wstring val = m_Measure->GetStringValue(false, 1, 0, false);
+		if (m_Measure)  //read from the measure
-		if (!val.empty())
 		{
-			// Load the new image
+			std::wstring val = m_Measure->GetStringValue(false, 1, 0, false);
-			val = m_MeterWindow->MakePathAbsolute(m_Path + val);
+			if (!val.empty())
-			if (val != m_ImageName) 
 			{
-				m_ImageName = val;
+				val = m_MeterWindow->MakePathAbsolute(m_Path + val);
-				LoadImage(true);
+				if (val != m_ImageName)
-			}
+				{
-			else
+					m_ImageName = val;
-			{
+					LoadImage(true);
-				LoadImage(false);
+				}
+				else
+				{
+					LoadImage(false);
+				}
 			}
+			return true;
+		}
+		else if (m_DynamicVariables)  //read from the skin
+		{
+			LoadImage(m_NeedsUpdate);
+			return true;
 		}
-		return true;
 	}
 	return false;
 }

Library/MeterImage.h

@@ -45,6 +45,7 @@ private:
 	Gdiplus::Bitmap* m_Bitmap;			// The bitmap
 	std::wstring m_ImageName;			// Name of the image
 	std::wstring m_Path;
+	bool m_NeedsUpdate;
 	bool m_WidthDefined;
 	bool m_HeightDefined;
 	bool m_PreserveAspectRatio;			// If true, aspect ratio of the image is preserved when the image is scaled

Library/MeterWindow.cpp

@@ -1401,8 +1401,10 @@ void CMeterWindow::ReadSkin()
 
 	m_RightMouseDownAction = m_Parser.ReadString(L"Rainmeter", L"RightMouseDownAction", L"");
 	m_LeftMouseDownAction = m_Parser.ReadString(L"Rainmeter", L"LeftMouseDownAction", L"");
+	m_MiddleMouseDownAction = m_Parser.ReadString(L"Rainmeter", L"MiddleMouseDownAction", L"");
 	m_RightMouseUpAction = m_Parser.ReadString(L"Rainmeter", L"RightMouseUpAction", L"");
 	m_LeftMouseUpAction = m_Parser.ReadString(L"Rainmeter", L"LeftMouseUpAction", L"");
+	m_MiddleMouseUpAction = m_Parser.ReadString(L"Rainmeter", L"MiddleMouseUpAction", L"");
 	m_MouseOverAction = m_Parser.ReadString(L"Rainmeter", L"MouseOverAction", L"");
 	m_MouseLeaveAction = m_Parser.ReadString(L"Rainmeter", L"MouseLeaveAction", L"");
 	m_OnRefreshAction = m_Parser.ReadString(L"Rainmeter", L"OnRefreshAction", L"");
@@ -2931,6 +2933,56 @@ LRESULT CMeterWindow::OnRightButtonUp(WPARAM wParam, LPARAM lParam)
 	return 0;
 }
 
+/*
+** OnMiddleButtonDown
+**
+** Runs the action when middle mouse button is down
+**
+*/
+LRESULT CMeterWindow::OnMiddleButtonDown(WPARAM wParam, LPARAM lParam) 
+{
+	POINT pos;
+	pos.x = (SHORT)LOWORD(lParam); 
+	pos.y = (SHORT)HIWORD(lParam); 
+	if (m_Message == WM_NCMBUTTONDOWN)
+	{
+		// Transform the point to client rect
+		RECT rect;
+		GetWindowRect(m_Window, &rect);
+		pos.x = pos.x - rect.left;
+		pos.y = pos.y - rect.top;
+	}
+
+	DoAction(pos.x, pos.y, MOUSE_MMB_DOWN, false);
+
+	return 0;
+}
+
+/*
+** OnMiddleButtonUp
+**
+** Runs the action when middle mouse button is up
+**
+*/
+LRESULT CMeterWindow::OnMiddleButtonUp(WPARAM wParam, LPARAM lParam) 
+{
+	POINT pos;
+	pos.x = (SHORT)LOWORD(lParam); 
+	pos.y = (SHORT)HIWORD(lParam); 
+	if (m_Message == WM_NCMBUTTONUP)
+	{
+		// Transform the point to client rect
+		RECT rect;
+		GetWindowRect(m_Window, &rect);
+		pos.x = pos.x - rect.left;
+		pos.y = pos.y - rect.top;
+	}
+
+	DoAction(pos.x, pos.y, MOUSE_MMB_UP, false);
+
+	return 0;
+}
+
 /*
 ** OnContextMenu
 **
@@ -3016,6 +3068,24 @@ bool CMeterWindow::DoAction(int x, int y, MOUSE mouse, bool test)
 				}
 				break;
 
+			case MOUSE_MMB_DOWN:
+				
+				if (!((*j)->GetMiddleMouseDownAction().empty()))
+				{
+					if (!test) m_Rainmeter->ExecuteCommand((*j)->GetMiddleMouseDownAction().c_str(), this);
+					return true;
+				}
+				break;
+
+			case MOUSE_MMB_UP:
+				
+				if (!((*j)->GetMiddleMouseUpAction().empty()))
+				{
+					if (!test) m_Rainmeter->ExecuteCommand((*j)->GetMiddleMouseUpAction().c_str(), this);
+					return true;
+				}
+				break;
+
 			case MOUSE_OVER:
 				if (!(*j)->IsMouseOver())
 				{
@@ -3220,6 +3290,10 @@ LRESULT CALLBACK CMeterWindow::WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPAR
 	MESSAGE(OnLeftButtonDown, WM_LBUTTONDOWN)
 	MESSAGE(OnLeftButtonUp, WM_LBUTTONUP)
 	MESSAGE(OnLeftButtonUp, WM_NCLBUTTONUP)
+	MESSAGE(OnMiddleButtonDown, WM_NCMBUTTONDOWN)
+	MESSAGE(OnMiddleButtonDown, WM_MBUTTONDOWN)
+	MESSAGE(OnMiddleButtonUp, WM_MBUTTONUP)
+	MESSAGE(OnMiddleButtonUp, WM_NCMBUTTONUP)
 	MESSAGE(OnWindowPosChanging, WM_WINDOWPOSCHANGING)
 	MESSAGE(OnCopyData, WM_COPYDATA)
 	MESSAGE(OnDelayedExecute, WM_DELAYED_EXECUTE)

Library/MeterWindow.h

@@ -44,6 +44,8 @@ enum MOUSE
 	MOUSE_LMB_UP,
 	MOUSE_RMB_DOWN,
 	MOUSE_RMB_UP,
+	MOUSE_MMB_DOWN,
+	MOUSE_MMB_UP,
 	MOUSE_OVER,
 	MOUSE_LEAVE
 };
@@ -193,12 +195,14 @@ protected:
 	LRESULT OnContextMenu(WPARAM wParam, LPARAM lParam);
 	LRESULT OnLeftButtonDown(WPARAM wParam, LPARAM lParam);
 	LRESULT OnRightButtonDown(WPARAM wParam, LPARAM lParam);
+	LRESULT OnMiddleButtonDown(WPARAM wParam, LPARAM lParam);
 	LRESULT OnLeftButtonUp(WPARAM wParam, LPARAM lParam);
 	LRESULT OnRightButtonUp(WPARAM wParam, LPARAM lParam);
+	LRESULT OnMiddleButtonUp(WPARAM wParam, LPARAM lParam);
 	LRESULT OnDelayedExecute(WPARAM wParam, LPARAM lParam);
 	LRESULT OnDelayedRefresh(WPARAM wParam, LPARAM lParam);
 	LRESULT OnDelayedQuit(WPARAM wParam, LPARAM lParam);
-	LRESULT OnSettingChange(WPARAM wParam, LPARAM lParam); 
+	LRESULT OnSettingChange(WPARAM wParam, LPARAM lParam);  
 
 
 private:
@@ -232,8 +236,10 @@ private:
 
 	std::wstring m_RightMouseDownAction;		// Action to run when right mouse is pressed
 	std::wstring m_LeftMouseDownAction;			// Action to run when left mouse is pressed
+	std::wstring m_MiddleMouseDownAction;		// Action to run when middle mouse is pressed
 	std::wstring m_RightMouseUpAction;			// Action to run when right mouse is released
 	std::wstring m_LeftMouseUpAction;			// Action to run when left mouse is released
+	std::wstring m_MiddleMouseUpAction;			// Action to run when middle mouse is released
 	std::wstring m_MouseOverAction;				// Action to run when mouse goes over the window
 	std::wstring m_MouseLeaveAction;			// Action to run when mouse leaves the window
 	std::wstring m_OnRefreshAction;				// Action to run when window is initialized