doc: add a note that middle-button dragging is not possible on sticks

Just to have something to point bug reporters to.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

diff --git a/doc/scrolling.dox b/doc/scrolling.dox
index 94aa815..61d58f3 100644 (file)
--- a/doc/scrolling.dox
+++ b/doc/scrolling.dox
@@ -55,6 +55,10 @@ a designated button is held down. For example, Lenovo devices provide a
 <a href="http://en.wikipedia.org/wiki/Pointing_stick">pointing stick</a> that emulates
 scroll events when the trackstick's middle mouse button is held down.
 
+@note On-button scrolling is enabled by default for pointing sticks. This
+prevents middle-button dragging; all motion events while the middle button is
+down are converted to scroll events.
+
 @image html button-scrolling.svg "Button scrolling"
 
 The button may be changed with