TIP:		94
Title:		Add Listbox -activestyle Option
Version:	$Revision: 1.5 $
Author:		Jeff Hobbs <JeffH@ActiveState.com>
State:		Final
Type:		Project
Created:	29-May-2002
Tcl-Version:	8.4
Vote:		Done
Post-History:	

~ Abstract

This TIP proposes to add a [[-activestyle]] option to the [[listbox]]
widget that would control what style the active element has when the
widget has focus (currently hard-coded to be underlined).

~ Rationale

Tk has always had an underline on the active item in listboxes, which
is shown when the listbox has focus.  However this in incompatible
with the style of listboxes on Windows, especially as used in drop-down
boxes.  They instead have a thin dotted line to indicate the active
item.  In order to improve native look and feel, we would allow the
user to request the style which indicates the active item.

~ Specification

|    $listbox configure -activestyle none|underline|dotbox

The default would be underline, which stays consistent with the
current behavior.  ''dotbox'' is the Windows style, which is
essentially the dotted focus ring that any item with focus receives.
While Windows does have a special API (''DrawFocusRect'') to draw
this, it should be possible with the features of the dash patch to
emulate on Unix.  It may not be possible to draw a dotbox easily on
MacOS, in which case the option will be allowed, but nothing would be
drawn (rather than dropping back to underline).

~ Reference Implementation

This implementation is simple and would only extend one check in
''DisplayListbox'' for whether the underline should be drawn.

File: ''tcl/generix/tkListbox.c''

Function: ''DisplayListbox''

~ Copyright

This document has been placed in the public domain.