How to reuse comment tools without reselecting

No and No. The commenting tools are meant to be used one at a time. Sometimes it'd be nice if the the tools were sticky. But this unfortunately is not an option. The pencil tool is sticky because of how it's used. You might have to "lift" the pen several times for a single comment.

All keyboard shortcuts in Acrobat are pre-defined. The user has no control over them.

Boy wouldn't it be nice if Acrobat was a bit more customizable, like other programs, but it's not:(

Thom Parker
The source for PDF Scripting Info
[url=http://www.pdfScripting.com]pdfscripting.com[/url]

The Acrobat JavaScript Reference, Use it Early and Often
[url=http://www.adobe.com/devnet/acrobat/javascript.php]http://www.adobe.com/devnet/acrobat/javascript.php[/url]

Then most important JavaScript Development tool in Acrobat
[url=http://www.pdfscripting.com/public/34.cfm#JSIntro][b]The Console Window (Video tutorial)[/b][/url]
[url=http://www.acrobatusers.com/tutorials/2006/javascript_console][b]The Console Window(article)[/b][/url]

hi thom,

Task:- "make the comment & markup tool visible, when a comment enabled pdf is open in reader."i tried all ur solutions it works great in windows. but in mac, the code works for the first time . i know that in mac when we close a pdf it wont close the acrobat exe. this will work if we quit the acrobat exe and open a new one.

can u advice me how this can be solved.

You'll have to be more specific