converted old html tags to doxygen in osissues.dox

plus minor tidying in forms.dox and subclassing.dox



git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@6796 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

documentation/src/forms.dox

@@ -6,7 +6,7 @@
 This appendix describes the Forms compatibility included with FLTK.
 
 <center>
-<table border="1" width="90%">
+<table border="1" width="90%" bgcolor="#cccccc">
 <tr>
 <th align="center">
 Warning: The Forms compatility is deprecated and no longer maintained in FLTK1,

documentation/src/subclassing.dox

@@ -483,8 +483,9 @@ may be UTF-8) between applications:
 \li Fl::selection()
 \li Fl::selection_owner()
 
-It may be possible to cut/paste non-text data by using
-<A href="osissues.html#add_handler"><tt>Fl::add_handler()</tt></A>.
+It may be possible to cut/paste non-text data by using Fl::add_handler().
+Note that handling events beyond those provided by FLTK may be operating
+system specific. See \ref osissues for more details.
 
 \section subclassing_dragndrop Drag And Drop Support