diff --git a/arguments.c b/arguments.c
index 5ff7ed2c..ca6cc760 100644
--- a/arguments.c
+++ b/arguments.c
@@ -125,7 +125,7 @@ args_free(struct args *args)
 size_t
 args_print(struct args *args, char *buf, size_t len)
 {
-	size_t		 	 off;
+	size_t		 	 off, used;
 	int			 i;
 	const char		*quotes;
 	struct args_entry	*entry;
@@ -165,9 +165,12 @@ args_print(struct args *args, char *buf, size_t len)
 			quotes = "\"";
 		else
 			quotes = "";
-		off += xsnprintf(buf + off, len - off, "%s-%c %s%s%s",
+		used = xsnprintf(buf + off, len - off, "%s-%c %s%s%s",
 		    off != 0 ? " " : "", entry->flag, quotes, entry->value,
 		    quotes);
+		if (used > len - off)
+			used = len - off;
+		off += used;
 	}
 
 	/* And finally the argument vector. */
@@ -181,8 +184,11 @@ args_print(struct args *args, char *buf, size_t len)
 			quotes = "\"";
 		else
 			quotes = "";
-		off += xsnprintf(buf + off, len - off, "%s%s%s%s",
+		used = xsnprintf(buf + off, len - off, "%s%s%s%s",
 		    off != 0 ? " " : "", quotes, args->argv[i], quotes);
+		if (used > len - off)
+			used = len - off;
+		off += used;
 	}
 
 	return (off);
diff --git a/cmd-list.c b/cmd-list.c
index 82ae7480..6dc4493a 100644
--- a/cmd-list.c
+++ b/cmd-list.c
@@ -103,7 +103,7 @@ size_t
 cmd_list_print(struct cmd_list *cmdlist, char *buf, size_t len)
 {
 	struct cmd	*cmd;
-	size_t		 off;
+	size_t		 off, used;
 
 	off = 0;
 	TAILQ_FOREACH(cmd, &cmdlist->list, qentry) {
@@ -112,8 +112,12 @@ cmd_list_print(struct cmd_list *cmdlist, char *buf, size_t len)
 		off += cmd_print(cmd, buf + off, len - off);
 		if (off >= len)
 			break;
-		if (TAILQ_NEXT(cmd, qentry) != NULL)
-			off += xsnprintf(buf + off, len - off, " ; ");
+		if (TAILQ_NEXT(cmd, qentry) != NULL) {
+			used = xsnprintf(buf + off, len - off, " ; ");
+			if (used > len - off)
+				used = len - off;
+			off += used;
+		}
 	}
 	return (off);
 }
diff --git a/window-copy.c b/window-copy.c
index 6e4d6704..c33a4c3b 100644
--- a/window-copy.c
+++ b/window-copy.c
@@ -1194,8 +1194,8 @@ window_copy_write_line(
 		screen_write_puts(ctx, &gc, "%s", hdr);
 	} else if (py == last && data->inputtype != WINDOW_COPY_OFF) {
 		limit = sizeof hdr;
-		if (limit > screen_size_x(s))
-			limit = screen_size_x(s);
+		if (limit > screen_size_x(s) + 1)
+			limit = screen_size_x(s) + 1;
 		if (data->inputtype == WINDOW_COPY_NUMERICPREFIX) {
 			xoff = size = xsnprintf(hdr, limit,
 			    "Repeat: %u", data->numprefix);
@@ -1208,10 +1208,12 @@ window_copy_write_line(
 	} else
 		size = 0;
 
-	screen_write_cursormove(ctx, xoff, py);
-	screen_write_copy(ctx, data->backing, xoff,
-	    (screen_hsize(data->backing) - data->oy) + py,
-	    screen_size_x(s) - size, 1);
+	if (size < screen_size_x(s)) {
+		screen_write_cursormove(ctx, xoff, py);
+		screen_write_copy(ctx, data->backing, xoff,
+		    (screen_hsize(data->backing) - data->oy) + py,
+		    screen_size_x(s) - size, 1);
+	}
 
 	if (py == data->cy && data->cx == screen_size_x(s)) {
 		memcpy(&gc, &grid_default_cell, sizeof gc);