diff --git a/Source/control.cpp b/Source/control.cpp
index 752043d11..ee7c819f2 100644
--- a/Source/control.cpp
+++ b/Source/control.cpp
@@ -429,6 +429,13 @@ void ToggleSpell(int slot)
 	}
 }
 
+/**
+ * @brief Print letter to the backbuffer
+ * @param sx Backbuffer offset
+ * @param sy Backbuffer offset
+ * @param nCel Number of letter in Windows-1252
+ * @param col text_color color value
+ */
 void CPrintString(int sx, int sy, int nCel, char col)
 {
 	/// ASSERT: assert(gpBuffer);
@@ -497,7 +504,7 @@ void DrawPanelBox(int x, int y, int w, int h, int sx, int sy)
 	/// ASSERT: assert(gpBuffer);
 
 	nSrcOff = x + PANEL_WIDTH * y;
-	nDstOff = sx + BUFFER_WIDTH * sy + PANEL_LEFT;
+	nDstOff = sx + BUFFER_WIDTH * sy;
 
 	int hgt;
 	BYTE *src, *dst;
@@ -545,7 +552,7 @@ void SetFlaskHeight(BYTE *pCelBuff, int min, int max, int sx, int sy)
  * into the target buffer.
  * @param pCelBuff The flask cel buffer.
  * @param w Width of the cel.
- * @param nSrcOffset Offset of the source buffer from where the bytes will start to be copied from.
+ * @param nSrcOff Offset of the source buffer from where the bytes will start to be copied from.
  * @param pBuff Target buffer.
  * @param nDstOff Offset of the target buffer where the bytes will start to be copied to.
  * @param h How many lines of the source buffer that will be copied.
@@ -584,9 +591,9 @@ void DrawLifeFlask()
 		filled = 11;
 	filled += 2;
 
-	DrawFlask(pLifeBuff, 88, 277, gpBuffer, BUFFER_WIDTH * 499 + 173, filled);
+	DrawFlask(pLifeBuff, 88, 277, gpBuffer, SCREENXY(PANEL_LEFT + 109, PANEL_TOP - 13), filled);
 	if (filled != 13)
-		DrawFlask(pBtmBuff, PANEL_WIDTH, PANEL_WIDTH * filled + 2029, gpBuffer, BUFFER_WIDTH * filled + BUFFER_WIDTH * 499 + 173, 13 - filled);
+		DrawFlask(pBtmBuff, PANEL_WIDTH, PANEL_WIDTH * (filled + 3) + 109, gpBuffer, SCREENXY(PANEL_LEFT + 109, PANEL_TOP - 13 + filled), 13 - filled);
 }
 
 /**
@@ -619,9 +626,9 @@ void DrawManaFlask()
 		filled = 11;
 	filled += 2;
 
-	DrawFlask(pManaBuff, 88, 277, gpBuffer, BUFFER_WIDTH * 499 + 173 + 366, filled);
+	DrawFlask(pManaBuff, 88, 277, gpBuffer, SCREENXY(PANEL_LEFT + 475, PANEL_TOP - 13), filled);
 	if (filled != 13)
-		DrawFlask(pBtmBuff, PANEL_WIDTH, PANEL_WIDTH * filled + 2029 + 366, gpBuffer, BUFFER_WIDTH * filled + BUFFER_WIDTH * 499 + 173 + 366, 13 - filled);
+		DrawFlask(pBtmBuff, PANEL_WIDTH, PANEL_WIDTH * (filled + 3) + 475, gpBuffer, SCREENXY(PANEL_LEFT + 475, PANEL_TOP - 13 + filled), 13 - filled);
 }
 
 void control_update_life_mana()
@@ -772,9 +779,9 @@ void DrawCtrlPan()
 
 	for (i = 0; i < 6; i++) {
 		if (!panbtn[i])
-			DrawPanelBox(PanBtnPos[i][0] - PANEL_LEFT, PanBtnPos[i][1] - (PANEL_TOP - 16), 71, 20, PanBtnPos[i][0] + PANEL_X, PanBtnPos[i][1] + SCREEN_Y);
+			DrawPanelBox(PanBtnPos[i][0] - PANEL_LEFT, PanBtnPos[i][1] - (PANEL_TOP - 16), 71, 20, PanBtnPos[i][0] + SCREEN_X, PanBtnPos[i][1] + SCREEN_Y);
 		else
-			CelDraw(PanBtnPos[i][0] + PANEL_X, PanBtnPos[i][1] + (PANEL_Y - 334), pPanelButtons, i + 1, 71);
+			CelDraw(PanBtnPos[i][0] + SCREEN_X, PanBtnPos[i][1] + (PANEL_Y - 334), pPanelButtons, i + 1, 71);
 	}
 	if (numpanbtns == 8) {
 		CelDraw(87 + PANEL_X, 122 + PANEL_Y, pMultiBtns, panbtn[6] + 1, 33);
@@ -1453,7 +1460,16 @@ void DrawChr()
 }
 
 
-void MY_PlrStringXY(int x, int y, int width, char *pszStr, char col, int base)
+/**
+ * @brief Render text string to back buffer
+ * @param x Screen coordinate
+ * @param y Screen coordinate
+ * @param endX End of line in screen coordinate
+ * @param pszStr String to print, in Windows-1252 encoding
+ * @param col text_color color value
+ * @param base Letter spacing
+ */
+void MY_PlrStringXY(int x, int y, int endX, char *pszStr, char col, int base)
 {
 	BYTE c;
 	char *tmp;
@@ -1461,7 +1477,7 @@ void MY_PlrStringXY(int x, int y, int width, char *pszStr, char col, int base)
 
 	sx = x + SCREEN_X;
 	sy = y + SCREEN_Y;
-	widthOffset = width - x + 1;
+	widthOffset = endX - x + 1;
 	line = 0;
 	screen_x = 0;
 	tmp = pszStr;
@@ -1503,7 +1519,7 @@ void DrawLevelUpIcon()
 
 	if (!stextflag) {
 		nCel = lvlbtndown ? 3 : 2;
-		ADD_PlrStringXY(0, 303, 120, "Level Up", COL_WHITE);
+		ADD_PlrStringXY(PANEL_LEFT + 0, PANEL_TOP - 49, PANEL_LEFT + 120, "Level Up", COL_WHITE);
 		CelDraw(40 + PANEL_X, -17 + PANEL_Y, pChrButtons, nCel, 41);
 	}
 }
@@ -1647,7 +1663,7 @@ void RedBack()
 	if (leveltype != DTYPE_HELL) {
 		dst = &gpBuffer[SCREENXY(0, 0)];
 		tbl = &pLightTbl[idx];
-		for (h = PANEL_TOP; h; h--, dst += BUFFER_WIDTH - SCREEN_WIDTH) {
+		for (h = VIEWPORT_HEIGHT; h; h--, dst += BUFFER_WIDTH - SCREEN_WIDTH) {
 			for (w = SCREEN_WIDTH; w; w--) {
 				*dst = tbl[*dst];
 				dst++;
@@ -1656,7 +1672,7 @@ void RedBack()
 	} else {
 		dst = &gpBuffer[SCREENXY(0, 0)];
 		tbl = &pLightTbl[idx];
-		for (h = PANEL_TOP; h; h--, dst += BUFFER_WIDTH - SCREEN_WIDTH) {
+		for (h = VIEWPORT_HEIGHT; h; h--, dst += BUFFER_WIDTH - SCREEN_WIDTH) {
 			for (w = SCREEN_WIDTH; w; w--) {
 				if (*dst >= 32)
 					*dst = tbl[*dst];
diff --git a/Source/gmenu.cpp b/Source/gmenu.cpp
index 80439fba4..bf562ba81 100644
--- a/Source/gmenu.cpp
+++ b/Source/gmenu.cpp
@@ -45,7 +45,7 @@ void gmenu_draw_pause()
 		RedBack();
 	if (!sgpCurrentMenu) {
 		light_table_index = 0;
-		gmenu_print_text(316 + PANEL_LEFT, -16 + PANEL_TOP, "Pause");
+		gmenu_print_text(316 + PANEL_LEFT, 336, "Pause");
 	}
 }
 
diff --git a/Source/minitext.cpp b/Source/minitext.cpp
index 37e83c0a8..79139b54c 100644
--- a/Source/minitext.cpp
+++ b/Source/minitext.cpp
@@ -75,7 +75,7 @@ void InitQTextMsg(int m)
 void DrawQTextBack()
 {
 	CelDraw(PANEL_X + 24, 487, pTextBoxCels, 1, 591);
-	trans_rect(27, 28, 585, 297);
+	trans_rect(PANEL_LEFT + 27, 28, 585, 297);
 }
 
 void PrintQTextChr(int sx, int sy, BYTE *pCelBuff, int nCel)
@@ -106,7 +106,7 @@ void DrawQText()
 
 	p = qtextptr;
 	pnl = NULL;
-	tx = 112;
+	tx = 48 + PANEL_X;
 	ty = qtexty;
 
 	doneflag = FALSE;
@@ -149,7 +149,7 @@ void DrawQText()
 		if (pnl == NULL) {
 			pnl = p;
 		}
-		tx = 112;
+		tx = 48 + PANEL_X;
 		ty += 38;
 		if (ty > 501) {
 			doneflag = TRUE;
diff --git a/Source/scrollrt.cpp b/Source/scrollrt.cpp
index 45cbde6c1..5fa1deac0 100644
--- a/Source/scrollrt.cpp
+++ b/Source/scrollrt.cpp
@@ -825,23 +825,21 @@ static void DrawGame(int x, int y)
 	if (zoomflag)
 		return;
 
-	nSrcOff = SCREENXY(32, 159);
-	nDstOff = SCREENXY(0, 350);
+	nSrcOff = SCREENXY(32, VIEWPORT_HEIGHT / 2 - 17);
+	nDstOff = SCREENXY(0, VIEWPORT_HEIGHT - 2);
 	wdt = SCREEN_WIDTH / 2;
 	if (SCREEN_WIDTH == PANEL_WIDTH && SCREEN_HEIGHT == VIEWPORT_HEIGHT + PANEL_HEIGHT) {
 		if (chrflag || questlog) {
-			nSrcOff = SCREENXY(112, 159);
-			nDstOff = SCREENXY(320, 350);
+			nSrcOff = SCREENXY(112, VIEWPORT_HEIGHT / 2 - 17);
+			nDstOff = SCREENXY(320, VIEWPORT_HEIGHT - 2);
 			wdt = (SCREEN_WIDTH - 320) / 2;
 		} else if (invflag || sbookflag) {
-			nSrcOff = SCREENXY(112, 159);
-			nDstOff = SCREENXY(0, 350);
+			nSrcOff = SCREENXY(112, VIEWPORT_HEIGHT / 2 - 17);
+			nDstOff = SCREENXY(0, VIEWPORT_HEIGHT - 2);
 			wdt = (SCREEN_WIDTH - 320) / 2;
 		}
 	}
 
-	assert(gpBuffer);
-
 	int hgt;
 	BYTE *src, *dst1, *dst2;
 
@@ -849,7 +847,7 @@ static void DrawGame(int x, int y)
 	dst1 = &gpBuffer[nDstOff];
 	dst2 = &gpBuffer[nDstOff + BUFFER_WIDTH];
 
-	for (hgt = 176; hgt != 0; hgt--, src -= BUFFER_WIDTH + wdt, dst1 -= 2 * (BUFFER_WIDTH + wdt), dst2 -= 2 * (BUFFER_WIDTH + wdt)) {
+	for (hgt = VIEWPORT_HEIGHT / 2; hgt != 0; hgt--, src -= BUFFER_WIDTH + wdt, dst1 -= 2 * (BUFFER_WIDTH + wdt), dst2 -= 2 * (BUFFER_WIDTH + wdt)) {
 		for (i = wdt; i != 0; i--) {
 			*dst1++ = *src;
 			*dst1++ = *src;
diff --git a/Source/stores.cpp b/Source/stores.cpp
index dea406c06..c0bc63277 100644
--- a/Source/stores.cpp
+++ b/Source/stores.cpp
@@ -117,7 +117,7 @@ void FreeStoreMem()
 void DrawSTextBack()
 {
 	CelDraw(PANEL_X + 344, 487, pSTextBoxCels, 1, 271);
-	trans_rect(347, 28, 265, 297);
+	trans_rect(PANEL_LEFT + 347, 28, 265, 297);
 }
 
 void PrintSString(int x, int y, BOOL cjustflag, char *str, char col, int val)
@@ -161,7 +161,7 @@ void PrintSString(int x, int y, BOOL cjustflag, char *str, char col, int val)
 	}
 	if (!cjustflag && val >= 0) {
 		sprintf(valstr, "%i", val);
-		sx = 656 - x;
+		sx = PANEL_X + 592 - x;
 		for (i = strlen(valstr) - 1; i >= 0; i--) {
 			c = fontframe[gbFontTransTbl[(BYTE)valstr[i]]];
 			sx -= fontkern[c] + 1;
@@ -171,7 +171,7 @@ void PrintSString(int x, int y, BOOL cjustflag, char *str, char col, int val)
 		}
 	}
 	if (stextsel == y) {
-		CelDraw(cjustflag ? xx + x + k + 4 : 660 - x, s + 205, pSPentSpn2Cels, PentSpn2Frame, 12);
+		CelDraw(cjustflag ? (xx + x + k + 4) : (PANEL_X + 596 - x), s + 205, pSPentSpn2Cels, PentSpn2Frame, 12);
 	}
 }
 
@@ -181,13 +181,13 @@ void DrawSLine(int y)
 
 	sy = y * 12;
 	if (stextsize == 1) {
-		xy = SCREENXY(26, 25);
-		yy = BUFFER_WIDTH * (sy + 198) + 26 + 64;
+		xy = SCREENXY(PANEL_LEFT + 26, 25);
+		yy = BUFFER_WIDTH * (sy + 198) + 26 + PANEL_X;
 		width = 586 / 4;
 		line = BUFFER_WIDTH - 586;
 	} else {
-		xy = SCREENXY(346, 25);
-		yy = BUFFER_WIDTH * (sy + 198) + 346 + 64;
+		xy = SCREENXY(PANEL_LEFT + 346, 25);
+		yy = BUFFER_WIDTH * (sy + 198) + 346 + PANEL_X;
 		width = 266 / 4;
 		line = BUFFER_WIDTH - 266;
 	}
diff --git a/defs.h b/defs.h
index a23a4a605..99fbde166 100644
--- a/defs.h
+++ b/defs.h
@@ -128,7 +128,7 @@
 #define RIGHT_PANEL		(SCREEN_WIDTH - 320)
 #define RIGHT_PANEL_X	(SCREEN_X + RIGHT_PANEL)
 
-#if SCREEN_WIDTH == PANEL_WIDTH
+#if SCREEN_WIDTH <= PANEL_WIDTH
 #define VIEWPORT_HEIGHT	(SCREEN_HEIGHT - PANEL_HEIGHT)
 #else
 #define VIEWPORT_HEIGHT	SCREEN_HEIGHT