(svn r23442) -Fix [FS#4511]: document that some video card drivers have trouble going to 8bpp mode

known-bugs.txt

@@ -326,6 +326,19 @@ Unreadable characters for non-latin locales [FS#4607]
 	8 bits blitter there are not enough colours to properly perform the
 	anti-aliasing.
 
+(Temporary) wrong colours when switching to full screen [FS#4511]:
+	On Windows it can happen that you temporarily see wrong colours
+	when switching to full screen OpenTTD, either by starting
+	OpenTTD in full screen mode, changing to full screen mode or by
+	ALT-TAB-ing into a full screen OpenTTD. This is caused by the
+	fact that OpenTTD, by default, uses 8bpp paletted output. The
+	wrong colours you are seeing is a temporary effect of the video
+	driver switching to 8bpp palette mode.
+
+	This issue can be worked around in two ways:
+		a) Setting fullscreen_bpp to 32
+		b) Setting up the 32bpp-anim or 32bpp-optimized blitter
+
 Train does not crash with itself [FS#4635]:
 	When a train drives in a circle the front engine passes through
 	wagons of the same train without crashing. This is intentional.