diff --git a/src/highlight.c b/src/highlight.c
index 9ce6102..6291f24 100644
--- a/src/highlight.c
+++ b/src/highlight.c
@@ -2929,7 +2929,12 @@
 #  endif
 	at_en.ae_u.cterm.fg_rgb = GUI_MCH_GET_RGB2(sgp->sg_gui_fg);
 	at_en.ae_u.cterm.bg_rgb = GUI_MCH_GET_RGB2(sgp->sg_gui_bg);
-	at_en.ae_u.cterm.ul_rgb = GUI_MCH_GET_RGB2(sgp->sg_gui_sp);
+	// Only use the underline/undercurl color when used, it may clear the
+	// background color if not supported.
+	if (sgp->sg_cterm & (HL_UNDERLINE | HL_UNDERCURL))
+	    at_en.ae_u.cterm.ul_rgb = GUI_MCH_GET_RGB2(sgp->sg_gui_sp);
+	else
+	    at_en.ae_u.cterm.ul_rgb = INVALCOLOR;
 	if (at_en.ae_u.cterm.fg_rgb == INVALCOLOR
 		&& at_en.ae_u.cterm.bg_rgb == INVALCOLOR)
 	{
diff --git a/src/term.c b/src/term.c
index c024fce..b4b5c09 100644
--- a/src/term.c
+++ b/src/term.c
@@ -4819,6 +4819,11 @@
 			if (version < 95)
 			    is_not_xterm = TRUE;
 
+			// With the real Xterm setting the underline RGB color
+			// clears the background color, disable "t_8u".
+			if (!is_not_xterm && *T_8U != NUL)
+			    T_8U = empty_option;
+
 			// Only request the cursor style if t_SH and t_RS are
 			// set. Only supported properly by xterm since version
 			// 279 (otherwise it returns 0x18).
diff --git a/src/version.c b/src/version.c
index 377928c..0530106 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    906,
+/**/
     905,
 /**/
     904,