diff --git a/plugins/mouse/mouserc_parse.l b/plugins/mouse/mouserc_parse.l
index 6e577d89..c00728c1 100644
--- a/plugins/mouse/mouserc_parse.l
+++ b/plugins/mouse/mouserc_parse.l
@@ -21,7 +21,7 @@ static void gotfield();
 static void addbinding();
 %}
 
-field [-A-Za-z0-9]+
+field [A-Za-z0-9][-A-Za-z0-9]*[^-]
 sep [ \t]+
 white [ \t]*