''[MGS]'' [[2003/08/10]] - Setting the listbox ''-exportselection'' option to 0 prevents the listbox selection from being exported (surprise!). It also prevents the selection being cleared when making another selection. Sometimes I like to be able to export the selection, but not have it cleared by selecting something else. Here's how to do it :

 # listsel.tcl --

 # Listbox selection handling.

 # ======================================================================

 proc listbox:select {W} {

   selection clear -displayof $W
   selection own -command {} $W
   selection handle -type UTF8_STRING \
     $W [list [namespace current]::listbox:handle $W]
   selection handle \
     $W [list [namespace current]::listbox:handle $W]

 }

 # ======================================================================

 proc listbox:handle {W offset maxChars} {

 # ----------------------------------------------------------------------

   set list {}
   foreach index [$W curselection] { lappend list [$W get $index] }

   set text [join $list \n]

 # ----------------------------------------------------------------------

   return [string range $text $offset [expr {$offset+$maxChars-1}]]

 }

 # ======================================================================

   # demo code
   listbox .l \
     -exportselection 0 \
     -selectmode extended \
     -yscrollcommand [list .y set]

   scrollbar .y -orient vertical -command [list .l yview]

   pack .y -side right -expand 0 -fill y
   pack .l -side left  -expand 1 -fill both

   for {set i 1} {$i <= 20} {incr i} {
     .l insert end "This is listbox item $i"
   }

   bind .l <<ListboxSelect>> [list listbox:select %W]

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Make a selection in the listbox, then you should be able to paste the contents of the selected lines into a text widget (for instance) or another application.

This is similar in principle to [label selection].

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[Category GUI]