Previously the logic was to set "usesMouse" (Emulation
MODE_Mouse100{0,1,2,3}) to false to indicate that the program running
in the terminal supports handling mouse events itself, i.e. the program
is interested in receiving Mouse Tracking events; or set to true otherwise.
Since this was confusing, use the inverse logic by replacing "usesMouse"
with "usesMouseTracking".
"usesMouseTracking" is set to true when the program running in the shell
indicates it's interested in receiving Mouse Tracking events. Or false
otherwise.
For example, vim indicates it's interested in receiving Mouse Tracking
evnets when using visual mouse mode:
http://vimdoc.sourceforge.net/htmldoc/intro.html#Normal
Mouse Tracking is an XTerm extension, for more information examine:
http://invisible-island.net/xterm/ctlseqs/ctlseqs.html#h2-Mouse-Tracking