From 08287edd61aa129a89d188667d7bf0f3ae143b0e Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Mon, 18 Dec 2023 16:26:02 -0500
Subject: [PATCH] Don't disable the colour burst in mixed mode.

---
 Machines/Apple/AppleII/Video.hpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/Machines/Apple/AppleII/Video.hpp b/Machines/Apple/AppleII/Video.hpp
index 9cd75093c..895a9da7c 100644
--- a/Machines/Apple/AppleII/Video.hpp
+++ b/Machines/Apple/AppleII/Video.hpp
@@ -460,7 +460,10 @@ template <class BusHandler, bool is_iie> class Video: public VideoBase {
 					}
 
 					int second_blank_start;
-					if(!is_text_mode(graphics_mode(row_+1))) {
+					// Colour burst is present on all lines of the display if graphics mode is enabled on the top
+					// portion; therefore use the graphics mode on line 0 rather than the current line, to avoid
+					// disabling it in mixed modes.
+					if(!is_text_mode(graphics_mode(0))) {
 						const int colour_burst_start = std::max(first_sync_column + sync_length + 1, column_);
 						const int colour_burst_end = std::min(first_sync_column + sync_length + 4, ending_column);
 						if(colour_burst_end > colour_burst_start) {