; Add commentary to w32inevt.c

* src/w32inevt.c (do_mouse_event): Comment on mouse
coordinates in console mouse-wheel events.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/w32inevt.c b/src/w32inevt.c
index 1a901d4e0aa..4312e52b6b4 100644
--- a/src/w32inevt.c
+++ b/src/w32inevt.c
@@ -534,6 +534,12 @@ do_mouse_event (MOUSE_EVENT_RECORD *event,
     case MOUSE_HWHEELED:
       {
 	struct frame *f = get_frame ();
+	/* Mouse positions in console wheel events are reported to
+	   ReadConsoleInput relative to the display's top-left
+	   corner(!), not relative to the origin of the console screen
+	   buffer.  This makes these coordinates unusable; e.g.,
+	   scrolling the tab-line in general doesn't work.
+	   FIXME (but how?).  */
 	int mx = event->dwMousePosition.X, my = event->dwMousePosition.Y;
 	bool down_p = (event->dwButtonState & 0x10000000) != 0;