The code below initializes a two-page Tk::NoteBook, each page of which contains a Tk::Entry. It tries to generate <KeyRelease> event for Tk::Entry when its parent Tk::NoteBook page is raised, but fails.

Specifically, it seems strange that :

1. the Tk::Entry's KeyRelease event handler will **not** be called at the first **two** page raise event triggered by mouse click;

2. starting from the third page raise event triggered by mouse click, **wrong** Tk::Entry's KeyRelease event handler will be called;

3. if Tk::Entry->focus is commented out in the page raise event handler, no <KeyRelease> event will be fired for Tk::Entry at all.

Could you comment about the reason of the error and suggest how to correctly trigger the Tk::Entry KeyRelease event in its container page's raise event ?

PS: Tk 804.033 & ActiveState Perl 5.20.2.2002 & Windows 10 10240 X64

The code: 

    use strict;
    use warnings;
    use Tk;
    use Tk::NoteBook;
    
    # Main Entry
    my $top = MainWindow->new(); $top->title("Test");
    my $nb = $top->NoteBook()->pack(-expand => 1, -fill => 'both');
    InitializeNoteBookPage($nb->add('page1', -label => 'Page 1'), "Lab
+el for Page 1");
    InitializeNoteBookPage($nb->add('page2', -label => 'Page 2'), "Lab
+el for Page 2");
    Tk::MainLoop();
    
    # Subroutines start here
    sub InitializeNoteBookPage{
        my($nbpage, $label_description) = @_;
    
        # Widget Initialization
        my($_label_1) = $nbpage->Label( -text   => $label_description,
+ );
        my($_entry_1) = $nbpage->Entry( -width  => 0, );    
    
        # Geometry Management
        $_label_1->grid( -in => $nbpage, -column => 1, -row => 1, -col
+umnspan => 1, -ipadx => 0, -ipady => 0, -padx => 0, -pady => 0, -rows
+pan => 1, -sticky => "" );
        $_entry_1->grid( -in => $nbpage, -column => 2, -row => 1, -col
+umnspan => 1, -ipadx => 0, -ipady => 0, -padx => 0, -pady => 0, -rows
+pan => 1, -sticky => "ew" );    
    
        # Resize Behavior
        $nbpage->gridRowconfigure   (1, -weight => 0, -minsize => 50, 
+ -pad => 0);
        $nbpage->gridColumnconfigure(1, -weight => 0, -minsize => 400,
+ -pad => 0);
        $nbpage->gridColumnconfigure(2, -weight => 0, -minsize => 400,
+ -pad => 0);
        
        # Event callbacks
        $_entry_1->bind("<KeyRelease>", sub {
            print $nbpage->name()." ".$_entry_1->name()." KeyRelease f
+ired\n";
        } );
            
        $nb->pageconfigure($nbpage->name(), -raisecmd => sub {
            print "\n".$nbpage->name()." raised \n";
            print "Going to fire ".$nbpage->name()." ".$_entry_1->name
+()."KeyRelease\n";
            $_entry_1->focus(); # If this line is commented out, no <K
+eyRelease> event will be fired at all ?!
            $_entry_1->eventGenerate("<KeyRelease>");
            print "Any thing happened ?\n";
        } );
    }

[download]

The output: 

    page1 raised
    Going to fire page1 entryKeyRelease
    Any thing happened ?
    
    page2 raised
    Going to fire page2 entryKeyRelease
    Any thing happened ?
    
    page1 raised
    Going to fire page1 entryKeyRelease
    page2 entry KeyRelease fired
    Any thing happened ?
    
    page2 raised
    Going to fire page2 entryKeyRelease
    page1 entry KeyRelease fired
    Any thing happened ?
    
    page1 raised                        <--- using "Tab" + "LeftRight"
+ + "Space"
    Going to fire page1 entryKeyRelease
    Any thing happened ?
    page1 entry KeyRelease fired

[download]

In reply to Fail to generate event for Tk::Entry contained in Tk::NoteBook page by xcli

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