diff --git a/src/d_clisrv.c b/src/d_clisrv.c
index 36d13fc14..6e22dde23 100644
--- a/src/d_clisrv.c
+++ b/src/d_clisrv.c
@@ -401,8 +401,7 @@ static void ExtraDataTicker(void)
 							DEBFILE(va("player %d kicked [gametic=%u] reason as follows:\n", i, gametic));
 						}
 						CONS_Alert(CONS_WARNING, M_GetText("Got unknown net command [%s]=%d (max %d)\n"), sizeu1(curpos - bufferstart), *curpos, bufferstart[0]);
-						D_FreeTextcmd(gametic);
-						return;
+						break;
 					}
 				}
 			}
@@ -3308,7 +3307,7 @@ void SV_StopServer(void)
 	localtextcmd[0] = 0;
 	localtextcmd2[0] = 0;
 
-	for (i = 0; i < BACKUPTICS; i++)
+	for (i = firstticstosend; i < firstticstosend + BACKUPTICS; i++)
 		D_Clearticcmd(i);
 
 	consoleplayer = 0;
diff --git a/src/d_main.c b/src/d_main.c
index 4cdfb13d9..df3398752 100644
--- a/src/d_main.c
+++ b/src/d_main.c
@@ -730,11 +730,6 @@ void D_StartTitle(void)
 	CON_ToggleOff();
 
 	// Reset the palette
-#ifdef HWRENDER
-	if (rendermode == render_opengl)
-		HWR_SetPaletteColor(0);
-	else
-#endif
 	if (rendermode != render_none)
 		V_SetPaletteLump("PLAYPAL");
 }
@@ -1056,15 +1051,6 @@ void D_SRB2Main(void)
 
 	if (M_CheckParm("-password") && M_IsNextParm())
 		D_SetPassword(M_GetNextParm());
-	else
-	{
-		size_t z;
-		char junkpw[25];
-		for (z = 0; z < 24; z++)
-			junkpw[z] = (char)(rand() & 64)+32;
-		junkpw[24] = '\0';
-		D_SetPassword(junkpw);
-	}
 
 	// add any files specified on the command line with -file wadfile
 	// to the wad list
@@ -1223,7 +1209,7 @@ void D_SRB2Main(void)
 	CONS_Printf("R_Init(): Init SRB2 refresh daemon.\n");
 	R_Init();
 
-	// setting up sound	
+	// setting up sound
 	if (dedicated)
 	{
 		nosound = true;
diff --git a/src/d_netcmd.c b/src/d_netcmd.c
index 673d64fd8..727d5eff4 100644
--- a/src/d_netcmd.c
+++ b/src/d_netcmd.c
@@ -2656,10 +2656,12 @@ static void D_MD5PasswordPass(const UINT8 *buffer, size_t len, const char *salt,
 
 #define BASESALT "basepasswordstorage"
 static UINT8 adminpassmd5[16];
+static boolean adminpasswordset = false;
 
 void D_SetPassword(const char *pw)
 {
 	D_MD5PasswordPass((const UINT8 *)pw, strlen(pw), BASESALT, &adminpassmd5);
+	adminpasswordset = true;
 }
 
 // Remote Administration
@@ -2728,6 +2730,12 @@ static void Got_Login(UINT8 **cp, INT32 playernum)
 
 	READMEM(*cp, sentmd5, 16);
 
+	if (!adminpasswordset)
+	{
+		CONS_Printf(M_GetText("Password from %s failed (no password set).\n"), player_names[playernum]);
+		return;
+	}
+
 	if (client)
 		return;
 
@@ -3951,7 +3959,7 @@ static void Command_RestartAudio_f(void)
 	I_ShutdownSound();
 	I_StartupSound();
 	I_InitMusic();
-	
+
 // These must be called or no sound and music until manually set.
 
 	I_SetSfxVolume(cv_soundvolume.value);
@@ -3959,7 +3967,7 @@ static void Command_RestartAudio_f(void)
 	I_SetMIDIMusicVolume(cv_midimusicvolume.value);
 	if (Playing()) // Gotta make sure the player is in a level
 		P_RestoreMusic(&players[consoleplayer]);
-	
+
 }
 
 /** Quits a game and returns to the title screen.
diff --git a/src/hardware/hw_main.c b/src/hardware/hw_main.c
index 81021ef7f..a5fe6b673 100644
--- a/src/hardware/hw_main.c
+++ b/src/hardware/hw_main.c
@@ -2901,8 +2901,8 @@ static boolean HWR_CheckBBox(fixed_t *bspcoord)
 	py2 = bspcoord[checkcoord[boxpos][3]];
 
 	// check clip list for an open space
-	angle1 = R_PointToAngle(px1, py1) - dup_viewangle;
-	angle2 = R_PointToAngle(px2, py2) - dup_viewangle;
+	angle1 = R_PointToAngle2(dup_viewx>>1, dup_viewy>>1, px1>>1, py1>>1) - dup_viewangle;
+	angle2 = R_PointToAngle2(dup_viewx>>1, dup_viewy>>1, px2>>1, py2>>1) - dup_viewangle;
 
 	span = angle1 - angle2;
 
@@ -4228,6 +4228,9 @@ static void HWR_SplitSprite(gr_vissprite_t *spr)
 	i = 0;
 	temp = FLOAT_TO_FIXED(realtop);
 
+	if (spr->mobj->frame & FF_FULLBRIGHT)
+		lightlevel = 255;
+
 #ifdef ESLOPE
 	for (i = 1; i < sector->numlights; i++)
 	{
@@ -4235,14 +4238,16 @@ static void HWR_SplitSprite(gr_vissprite_t *spr)
 					: sector->lightlist[i].height;
 		if (h <= temp)
 		{
-			lightlevel = *list[i-1].lightlevel;
+			if (!(spr->mobj->frame & FF_FULLBRIGHT))
+				lightlevel = *list[i-1].lightlevel;
 			colormap = list[i-1].extra_colormap;
 			break;
 		}
 	}
 #else
 	i = R_GetPlaneLight(sector, temp, false);
-	lightlevel = *list[i].lightlevel;
+	if (!(spr->mobj->frame & FF_FULLBRIGHT))
+		lightlevel = *list[i].lightlevel;
 	colormap = list[i].extra_colormap;
 #endif
 
@@ -4257,7 +4262,8 @@ static void HWR_SplitSprite(gr_vissprite_t *spr)
 		// even if we aren't changing colormap or lightlevel, we still need to continue drawing down the sprite
 		if (!(list[i].flags & FF_NOSHADE) && (list[i].flags & FF_CUTSPRITES))
 		{
-			lightlevel = *list[i].lightlevel;
+			if (!(spr->mobj->frame & FF_FULLBRIGHT))
+				lightlevel = *list[i].lightlevel;
 			colormap = list[i].extra_colormap;
 		}
 
diff --git a/src/lua_consolelib.c b/src/lua_consolelib.c
index 566e73748..3239b7c5e 100644
--- a/src/lua_consolelib.c
+++ b/src/lua_consolelib.c
@@ -77,7 +77,9 @@ void Got_Luacmd(UINT8 **cp, INT32 playernum)
 
 deny:
 	//must be hacked/buggy client
-	lua_settop(gL, 0); // clear stack
+	if (gL) // check if Lua is actually turned on first, you dummmy -- Monster Iestyn 04/07/18
+		lua_settop(gL, 0); // clear stack
+
 	CONS_Alert(CONS_WARNING, M_GetText("Illegal lua command received from %s\n"), player_names[playernum]);
 	if (server)
 	{
diff --git a/src/m_fixed.c b/src/m_fixed.c
index ce7471a28..014457386 100644
--- a/src/m_fixed.c
+++ b/src/m_fixed.c
@@ -33,7 +33,9 @@
 */
 fixed_t FixedMul(fixed_t a, fixed_t b)
 {
-	return (fixed_t)((((INT64)a * b) ) / FRACUNIT);
+	// Need to cast to unsigned before shifting to avoid undefined behaviour
+	// for negative integers
+	return (fixed_t)(((UINT64)((INT64)a * b)) >> FRACBITS);
 }
 
 #endif //__USE_C_FIXEDMUL__
diff --git a/src/m_menu.c b/src/m_menu.c
index 0ab771579..79ac6800b 100644
--- a/src/m_menu.c
+++ b/src/m_menu.c
@@ -6543,7 +6543,7 @@ static void M_HandleSetupMultiPlayer(INT32 choice)
 			if (choice < 32 || choice > 127 || itemOn != 0)
 				break;
 			l = strlen(setupm_name);
-			if (l < MAXPLAYERNAME-1)
+			if (l < MAXPLAYERNAME)
 			{
 				S_StartSound(NULL,sfx_menu1); // Tails
 				setupm_name[l] =(char)choice;
diff --git a/src/p_setup.c b/src/p_setup.c
index 52cd6ddbb..d8c913e0f 100644
--- a/src/p_setup.c
+++ b/src/p_setup.c
@@ -2503,11 +2503,6 @@ boolean P_SetupLevel(boolean skipprecip)
 
 
 	// Reset the palette
-#ifdef HWRENDER
-	if (rendermode == render_opengl)
-		HWR_SetPaletteColor(0);
-	else
-#endif
 	if (rendermode != render_none)
 		V_SetPaletteLump("PLAYPAL");
 
@@ -3003,7 +2998,7 @@ boolean P_AddWadFile(const char *wadfilename, char **firstmapname)
 
 	if ((numlumps = W_LoadWadFile(wadfilename)) == INT16_MAX)
 	{
-		CONS_Printf(M_GetText("Errors occured while loading %s; not added.\n"), wadfilename);
+		CONS_Printf(M_GetText("Errors occurred while loading %s; not added.\n"), wadfilename);
 		return false;
 	}
 	else wadnum = (UINT16)(numwadfiles-1);
diff --git a/src/sdl/i_video.c b/src/sdl/i_video.c
index 87ce84158..4eab0ae3c 100644
--- a/src/sdl/i_video.c
+++ b/src/sdl/i_video.c
@@ -658,6 +658,14 @@ static void Impl_HandleMouseButtonEvent(SDL_MouseButtonEvent evt, Uint32 type)
 
 	SDL_memset(&event, 0, sizeof(event_t));
 
+	// Ignore the event if the mouse is not actually focused on the window.
+	// This can happen if you used the mouse to restore keyboard focus;
+	// this apparently makes a mouse button down event but not a mouse button up event,
+	// resulting in whatever key was pressed down getting "stuck" if we don't ignore it.
+	// -- Monster Iestyn (28/05/18)
+	if (SDL_GetMouseFocus() != window)
+		return;
+
 	/// \todo inputEvent.button.which
 	if (USE_MOUSEINPUT)
 	{
diff --git a/src/st_stuff.c b/src/st_stuff.c
index 3562a9b71..72e0b6b94 100644
--- a/src/st_stuff.c
+++ b/src/st_stuff.c
@@ -210,17 +210,17 @@ void ST_doPaletteStuff(void)
 	else
 		palette = 0;
 
+#ifdef HWRENDER
+	if (rendermode == render_opengl)
+		palette = 0; // No flashpals here in OpenGL
+#endif
+
 	palette = min(max(palette, 0), 13);
 
 	if (palette != st_palette)
 	{
 		st_palette = palette;
 
-#ifdef HWRENDER
-		if (rendermode == render_opengl)
-			HWR_SetPaletteColor(0);
-		else
-#endif
 		if (rendermode != render_none)
 		{
 			V_SetPaletteLump(GetPalette()); // Reset the palette