diff --git a/uppsrc/CtrlCore/CtrlDraw.cpp b/uppsrc/CtrlCore/CtrlDraw.cpp
index eddbf18a0..0545819eb 100644
--- a/uppsrc/CtrlCore/CtrlDraw.cpp
+++ b/uppsrc/CtrlCore/CtrlDraw.cpp
@@ -21,7 +21,7 @@ void Ctrl::RefreshFrame(const Rect& r) {
 	LLOG("RefreshRect " << Name() << ' ' << r);
 	if(GuiPlatformRefreshFrameSpecial(r))
 		return;
-	if(!top) {
+	if(!top && !isdhctrl) {
 		if(InFrame())
 			parent->RefreshFrame(r + GetRect().TopLeft());
 		else
@@ -168,6 +168,10 @@ void  Ctrl::ScrollView(const Rect& _r, int dx, int dy)
 #else
 	if(IsFullRefresh() || !IsVisible())
 		return;
+	if(isdhctrl) {
+		Refresh(_r);
+		return;
+	}
 	Size vsz = GetSize();
 	dx = sgn(dx) * min(abs(dx), vsz.cx);
 	dy = sgn(dy) * min(abs(dy), vsz.cy);
diff --git a/uppsrc/CtrlCore/CtrlPos.cpp b/uppsrc/CtrlCore/CtrlPos.cpp
index 4155838c0..abceac62e 100644
--- a/uppsrc/CtrlCore/CtrlPos.cpp
+++ b/uppsrc/CtrlCore/CtrlPos.cpp
@@ -188,7 +188,7 @@ void Ctrl::SetPos0(LogPos p, bool _inframe)
 {
 	GuiLock __;
 	if(p == pos && inframe == _inframe) return;
-	if(parent) {
+	if(parent && !isdhctrl) {
 		if(!globalbackbuffer) {
 			Rect from = GetRect().Size();
 			Top *top = GetTopRect(from, true)->top;
diff --git a/uppsrc/CtrlCore/DHCtrl.cpp b/uppsrc/CtrlCore/DHCtrl.cpp
index d880f5deb..1ac261da2 100644
--- a/uppsrc/CtrlCore/DHCtrl.cpp
+++ b/uppsrc/CtrlCore/DHCtrl.cpp
@@ -46,6 +46,8 @@ void DHCtrl::NcDestroy()
 LRESULT DHCtrl::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
 {
 	GuiLock __;
+	if(message == WM_ERASEBKGND)
+		return 1L;
 	return DefWindowProc(hwnd, message, wParam, lParam);
 }
 
@@ -76,11 +78,14 @@ void DHCtrl::SyncHWND()
 	GuiLock __;
 	HWND phwnd = GetTopCtrl()->GetHWND();
 	if(phwnd) {
-		Rect r = GetScreenView();
-		Rect pr = GetScreenClient(phwnd);
-		SetWindowPos(hwnd, NULL, r.left - pr.left, r.top - pr.top, r.Width(), r.Height(),
-		             SWP_NOACTIVATE|SWP_NOZORDER);
-		ShowWindow(hwnd, IsVisible() ? SW_SHOW : SW_HIDE);
+		Rect r = GetScreenView() - GetScreenClient(phwnd).TopLeft();
+		if(r != current_pos || IsVisible() != (bool)current_visible) {
+			SetWindowPos(hwnd, NULL, r.left, r.top, r.Width(), r.Height(), SWP_NOACTIVATE|SWP_NOZORDER);
+			ShowWindow(hwnd, IsVisible() ? SW_SHOW : SW_HIDE);
+			Refresh();
+			current_pos = r;
+			current_visible = IsVisible();
+		}
 	}
 }
 
@@ -88,6 +93,8 @@ void DHCtrl::State(int reason)
 {
 	switch(reason) {
 	case OPEN:
+		current_pos = Null;
+		current_visible = Null;
 		OpenHWND();
 	default:
 		SyncHWND();
@@ -111,6 +118,17 @@ DHCtrl::~DHCtrl()
 	RemoveActive();
 }
 
+void Ctrl::UpdateDHCtrls()
+{ // we call this in WM_PAINT to force updating in single WM_PAINT, this makes things smoother e.g. with OpenGL in splitter
+	for(Ctrl *q = GetFirstChild(); q; q = q->GetNext()) {
+		DHCtrl *dh = dynamic_cast<DHCtrl *>(q);
+		if(dh)
+			UpdateWindow(dh->GetHWND());
+		q->UpdateDHCtrls();
+	}
+}
+
+
 #endif
 
 }
diff --git a/uppsrc/CtrlCore/Win32Ctrl.h b/uppsrc/CtrlCore/Win32Ctrl.h
index b0faa982d..37fa0f786 100644
--- a/uppsrc/CtrlCore/Win32Ctrl.h
+++ b/uppsrc/CtrlCore/Win32Ctrl.h
@@ -22,6 +22,8 @@ private:
 	static void RenderAllFormats();
 	static void DestroyClipboard();
 
+	void UpdateDHCtrls();
+
 public:
 	static Win32Event ExitLoopEvent;
 	static bool       endsession;
diff --git a/uppsrc/CtrlCore/Win32GuiA.h b/uppsrc/CtrlCore/Win32GuiA.h
index 0955fbc91..ce2dce93d 100644
--- a/uppsrc/CtrlCore/Win32GuiA.h
+++ b/uppsrc/CtrlCore/Win32GuiA.h
@@ -91,6 +91,9 @@ private:
 
 	static bool PreprocessMessageAll(MSG& msg);
 	
+	Rect current_pos = Null;
+	int  current_visible = Null;
+
 	friend class Ctrl;
 
 protected:
diff --git a/uppsrc/CtrlCore/Win32Proc.cpp b/uppsrc/CtrlCore/Win32Proc.cpp
index 72e8e8c62..89bdbc451 100644
--- a/uppsrc/CtrlCore/Win32Proc.cpp
+++ b/uppsrc/CtrlCore/Win32Proc.cpp
@@ -112,6 +112,8 @@ LRESULT Ctrl::WindowProc(UINT message, WPARAM wParam, LPARAM lParam) {
 	#endif
 			}
 			EndPaint(hwnd, &ps);
+			
+			UpdateDHCtrls(); // so that they are displayed withing the same WM_PAINT - looks better
 		}
 		return 0L;
 #ifndef PLATFORM_WINCE
diff --git a/uppsrc/GLCtrl/GLCtrl.cpp b/uppsrc/GLCtrl/GLCtrl.cpp
index 885fc348a..9a438cf75 100644
--- a/uppsrc/GLCtrl/GLCtrl.cpp
+++ b/uppsrc/GLCtrl/GLCtrl.cpp
@@ -43,7 +43,7 @@ Image GLCtrl::GLPane::MouseEvent(int event, Point p, int zdelta, dword keyflags)
 
 Vector<int> GLCtrl::Pick(int x, int y)
 {
-	pane.ActivateContext();
+//	pane.ActivateContext();
 	return picking.Pick(x, y, THISBACK2(GLResize, GetSize().cx, GetSize().cy), THISBACK(GLPickingPaint));
 }
 
diff --git a/uppsrc/GLCtrl/GLCtrl.h b/uppsrc/GLCtrl/GLCtrl.h
index 17cfa7701..1df666bc5 100644
--- a/uppsrc/GLCtrl/GLCtrl.h
+++ b/uppsrc/GLCtrl/GLCtrl.h
@@ -111,13 +111,12 @@ private:
 	struct GLPane : DHCtrl {
 		friend class GLCtrl;
 		
-		HDC    hDC;
-		HGLRC  hRC;
+	//	HDC    hDC;
+	//	HGLRC  hRC;
 		GLCtrl *ctrl;
 		
 	public:
-		GLPane() : hDC(NULL), hRC(NULL) { NoWantFocus(); }
-		~GLPane() { Destroy(); }
+		GLPane()/* : hDC(NULL), hRC(NULL)*/ { NoWantFocus(); }
 		
 		virtual void    State(int reason);
 		virtual LRESULT WindowProc(UINT message, WPARAM wParam, LPARAM lParam);
diff --git a/uppsrc/GLCtrl/Win32GLCtrl.cpp b/uppsrc/GLCtrl/Win32GLCtrl.cpp
index 4b4fe0cb9..1996bbb17 100644
--- a/uppsrc/GLCtrl/Win32GLCtrl.cpp
+++ b/uppsrc/GLCtrl/Win32GLCtrl.cpp
@@ -7,6 +7,81 @@ namespace Upp {
 #pragma comment( lib, "opengl32.lib" )	// Search For OpenGL32.lib While Linking
 #pragma comment( lib, "glu32.lib" )		// Search For GLu32.lib While Linking
 
+static HGLRC                 s_openGLContext; // we only have single OpenGL context for all windows
+static PIXELFORMATDESCRIPTOR s_pfd;
+static int                   s_pixelFormatID;
+
+void MakeGLContext(HWND hwnd, int depthBits, int stencilBits, int samples)
+{
+	ONCELOCK {
+		for(int pass = 0; pass < 2; pass++) {
+			HWND hWND = CreateWindow("UPP-CLASS-A", "Fake Window",
+			                         WS_CAPTION|WS_SYSMENU|WS_CLIPSIBLINGS|WS_CLIPCHILDREN,
+			                         0, 0, 1, 1, NULL, NULL,
+			                         NULL, NULL);
+			if(!hWND)
+				return;
+			HDC hDC = ::GetDC(hWND);
+			if(!hDC)
+				return;
+			memset(&s_pfd, 0, sizeof(s_pfd));
+			if(pass == 0) {
+				s_pfd.nSize = sizeof(s_pfd);
+				s_pfd.nVersion = 1;
+				s_pfd.dwFlags = PFD_DRAW_TO_WINDOW|PFD_SUPPORT_OPENGL|PFD_GENERIC_ACCELERATED|PFD_GENERIC_FORMAT;
+				s_pfd.iPixelType = PFD_TYPE_RGBA;
+				s_pfd.cColorBits = 32;
+				s_pfd.cAlphaBits = 8;
+				s_pfd.cDepthBits = 24;
+				s_pfd.cStencilBits = 8;
+				s_pfd.iLayerType = PFD_MAIN_PLANE;
+				s_pixelFormatID = ChoosePixelFormat(hDC, &s_pfd);
+			}
+			else {
+				Vector<int> attr;
+				attr
+					<< WGL_DRAW_TO_WINDOW_ARB << GL_TRUE
+					<< WGL_SUPPORT_OPENGL_ARB << GL_TRUE
+					<< WGL_DOUBLE_BUFFER_ARB << GL_TRUE
+					<< WGL_PIXEL_TYPE_ARB << WGL_TYPE_RGBA_ARB
+					<< WGL_ACCELERATION_ARB << WGL_FULL_ACCELERATION_ARB
+					<< WGL_COLOR_BITS_ARB << 32
+					<< WGL_ALPHA_BITS_ARB << 8
+					<< WGL_DEPTH_BITS_ARB << depthBits
+					<< WGL_STENCIL_BITS_ARB << stencilBits
+				;
+				if(samples > 1)
+					attr
+						<< WGL_SAMPLE_BUFFERS_ARB << GL_TRUE
+						<< WGL_SAMPLES_ARB << samples
+					;
+				attr << 0;
+				UINT numFormats;
+				if(!wglChoosePixelFormatARB(hDC, attr, NULL, 1, &s_pixelFormatID, &numFormats))
+					return;
+			}
+			
+			DescribePixelFormat(hDC, s_pixelFormatID, sizeof(PIXELFORMATDESCRIPTOR), &s_pfd);
+			if(!SetPixelFormat(hDC, s_pixelFormatID, &s_pfd))
+				return;
+	
+			if(pass == 0) {
+				HGLRC hRC = wglCreateContext(hDC);
+				wglMakeCurrent(hDC, hRC);
+				glewInit();
+				wglMakeCurrent(NULL, NULL);
+			    wglDeleteContext(hRC);
+			}
+			else
+				s_openGLContext = wglCreateContext(hDC);
+
+		    ReleaseDC(hWND, hDC);
+		    DestroyWindow(hWND);
+		}
+	}
+}
+
+
 void InitializeGlew()
 {
 	ONCELOCK { // create temporary window to initialize glew
@@ -19,22 +94,22 @@ void InitializeGlew()
 		HDC hDC = ::GetDC(hWND);
 		if(!hDC)
 			return;
-		PIXELFORMATDESCRIPTOR pfd;
-		memset(&pfd, 0, sizeof(pfd));
-		pfd.nSize = sizeof(pfd);
-		pfd.nVersion = 1;
-		pfd.dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL | PFD_GENERIC_ACCELERATED | PFD_GENERIC_FORMAT;
-//		if (ctrl->doubleBuffering) pfd.dwFlags |= PFD_DOUBLEBUFFER;
-		pfd.iPixelType = PFD_TYPE_RGBA;
-		pfd.cColorBits = 32;
-		pfd.cAlphaBits = 8;
-		pfd.cDepthBits = 24;
-		pfd.cStencilBits = 8;
-		pfd.iLayerType = PFD_MAIN_PLANE;
-		int pixelFormatID = ChoosePixelFormat(hDC, &pfd);
+		PIXELFORMATDESCRIPTOR s_pfd;
+		memset(&s_pfd, 0, sizeof(s_pfd));
+		s_pfd.nSize = sizeof(s_pfd);
+		s_pfd.nVersion = 1;
+		s_pfd.dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL | PFD_GENERIC_ACCELERATED | PFD_GENERIC_FORMAT;
+//		if (ctrl->doubleBuffering) s_pfd.dwFlags |= PFD_DOUBLEBUFFER;
+		s_pfd.iPixelType = PFD_TYPE_RGBA;
+		s_pfd.cColorBits = 32;
+		s_pfd.cAlphaBits = 8;
+		s_pfd.cDepthBits = 24;
+		s_pfd.cStencilBits = 8;
+		s_pfd.iLayerType = PFD_MAIN_PLANE;
+		int pixelFormatID = ChoosePixelFormat(hDC, &s_pfd);
 	
-		DescribePixelFormat(hDC, pixelFormatID, sizeof(PIXELFORMATDESCRIPTOR), &pfd);
-		SetPixelFormat(hDC, pixelFormatID, &pfd);
+		DescribePixelFormat(hDC, pixelFormatID, sizeof(PIXELFORMATDESCRIPTOR), &s_pfd);
+		SetPixelFormat(hDC, pixelFormatID, &s_pfd);
 
 		HGLRC hRC = wglCreateContext(hDC);
 		
@@ -49,110 +124,41 @@ void InitializeGlew()
 	}
 }
 
-void GLCtrl::GLPane::Init()
-{
-	InitializeGlew();
-
-	HWND hwnd = GetHWND();
-	if(!hwnd)
-		return;
-	hDC = ::GetDC(hwnd);
-	if(!hDC)
-		return;
-	int pixelFormatID;
-	PIXELFORMATDESCRIPTOR pfd;
-	memset(&pfd, 0, sizeof(pfd));
-
-	Vector<int> attr;
-	attr
-		<< WGL_DRAW_TO_WINDOW_ARB << GL_TRUE
-		<< WGL_SUPPORT_OPENGL_ARB << GL_TRUE
-		<< WGL_DOUBLE_BUFFER_ARB << GL_TRUE
-		<< WGL_PIXEL_TYPE_ARB << WGL_TYPE_RGBA_ARB
-		<< WGL_ACCELERATION_ARB << WGL_FULL_ACCELERATION_ARB
-		<< WGL_COLOR_BITS_ARB << 32
-		<< WGL_ALPHA_BITS_ARB << 8
-		<< WGL_DEPTH_BITS_ARB << ctrl->depthSize
-		<< WGL_STENCIL_BITS_ARB << ctrl->stencilSize
-	;
-	if(ctrl->numberOfSamples > 1)
-		attr
-			<< WGL_SAMPLE_BUFFERS_ARB << GL_TRUE
-			<< WGL_SAMPLES_ARB << ctrl->numberOfSamples
-		;
-	attr << 0;
-	UINT numFormats;
-	if(!wglChoosePixelFormatARB(hDC, attr, NULL, 1, &pixelFormatID, &numFormats)) {
-		Destroy();
-		return;
-	}
-
-	DescribePixelFormat(hDC, pixelFormatID, sizeof(pfd), &pfd);
-	if(!SetPixelFormat(hDC, pixelFormatID, &pfd)) {
-		Destroy();
-		return;
-	}
-	hRC = wglCreateContext(hDC);
-	ActivateContext();
-	glEnable(GL_MULTISAMPLE);
-
-	ctrl->GLInit();
-	ctrl->GLResize(GetSize().cx, GetSize().cy);
-	ctrl->GLPaint();
-}
-
-void GLCtrl::GLPane::Destroy()
-{
-	if (hDC != NULL && hRC != NULL)
-	{
-		ActivateContext();
-		ctrl->GLDone();
-		wglMakeCurrent(NULL, NULL);
-	}
-	
-	if(hRC)
-	    wglDeleteContext(hRC);
-	if(hDC)
-	    ReleaseDC(GetHWND(), hDC);
-}
-
-void GLCtrl::GLPane::ActivateContext()
-{
-	if (hRC != NULL && wglGetCurrentContext() != hRC)
-		wglMakeCurrent(hDC, hRC);
-}
-
 void GLCtrl::GLPane::State(int reason)
 {
-	if (reason == CLOSE)
-		Destroy();
-	
-	if ((reason == LAYOUTPOS || reason == POSITION) && hDC != NULL && hRC != NULL)
-	{
-		ActivateContext();
-		ctrl->GLResize(GetSize().cx, GetSize().cy);
-	}
-	
 	DHCtrl::State(reason);
 	
-	if (reason == OPEN)
-		Init();
+	if(reason == OPEN) {
+		HWND hwnd = GetHWND();
+		MakeGLContext(hwnd, ctrl->depthSize, ctrl->stencilSize, ctrl->numberOfSamples);
+		HDC hDC = GetDC(hwnd);
+		if(!SetPixelFormat(hDC, s_pixelFormatID, &s_pfd))
+			return;
+		ReleaseDC(hwnd, hDC);
+	}
 }
 
 LRESULT GLCtrl::GLPane::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
 {
-	if((message == WM_PAINT || message == WM_SIZE || message == WM_ERASEBKGND) && hDC && hRC)
-	{
+	if(message == WM_PAINT && s_openGLContext) {
+		static int i = 0;
 		PAINTSTRUCT ps;
-		BeginPaint(GetHWND(), &ps);
-		ActivateContext();
-		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
+		HWND hwnd = GetHWND();
+		BeginPaint(hwnd, &ps);
+		HDC hDC = ps.hdc;
+		wglMakeCurrent(hDC, s_openGLContext);
+		glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT|GL_STENCIL_BUFFER_BIT);
+		glEnable(GL_MULTISAMPLE);
+		Size sz = GetSize();
+		glViewport(0, 0, (GLsizei)sz.cx, (GLsizei)sz.cy);
 		ctrl->GLPaint();
 		if(ctrl->doubleBuffering)
 			SwapBuffers(hDC);
 		else
 			glFlush();
-		EndPaint(GetHWND(), &ps);
+		wglMakeCurrent(NULL, NULL);
+		ReleaseDC(hwnd, hDC);
+		EndPaint(hwnd, &ps);
 		return 0;
 	}
 	
diff --git a/uppsrc/GLDraw/GLDraw.h b/uppsrc/GLDraw/GLDraw.h
index 6d1836d8a..d3d2a67de 100644
--- a/uppsrc/GLDraw/GLDraw.h
+++ b/uppsrc/GLDraw/GLDraw.h
@@ -18,8 +18,9 @@
 namespace Upp {
 
 enum {
-	TEXTURE_LINEAR = 0x01,
-	TEXTURE_MIPMAP = 0x02,
+	TEXTURE_LINEAR     = 0x01,
+	TEXTURE_MIPMAP     = 0x02,
+	TEXTURE_COMPRESSED = 0x04,
 };
 
 GLuint CreateGLTexture(const Image& img, dword flags);
diff --git a/uppsrc/plugin/glew/glew.upp b/uppsrc/plugin/glew/glew.upp
index becb67099..e1799736a 100644
--- a/uppsrc/plugin/glew/glew.upp
+++ b/uppsrc/plugin/glew/glew.upp
@@ -1,9 +1,9 @@
 description "OpenGL extension wrangler library\3770,128,128";
 
 file
-	glew.c,
 	glew.h,
 	glxew.h,
 	wglew.h,
+	glew.c,
 	Copying;