wxWidgets trying to fill whole area - c++

Question

I've got a problem when I'm trying to prepare gui using wxWidgets.
I want to create some buttons which will cover whole area under the textbox.
It looks pretty nice when program starts, but when I want to resize it horizontally the buttons are not moving. Any ideas?
mainFrame::mainFrame(std::string title) : wxFrame(NULL, wxID_ANY, title, wxDefaultPosition, wxSize(800, 600))
{
wxBoxSizer* vertSizer = new wxBoxSizer(wxVERTICAL);
vertSizer->Add(
new wxTextCtrl(this, -1, "My text", wxDefaultPosition, wxSize(100,80), wxTE_MULTILINE),
1, // vertically stretchable
wxEXPAND | wxALL, // horizontally stretchable, borders all around
10); // Add text box to parent sizer
wxBoxSizer* horizSizer = new wxBoxSizer(wxHORIZONTAL); // Make child sizer, will contain buttons
wxSizerFlags ButtonFlags(1); // Make controls stretch hoizontally (to cover entire sizer area)
ButtonFlags.Expand().Center().Border(wxALL,10); // Make controls expand vertically, add border
horizSizer->Add(new wxButton(this,123,"OK"), ButtonFlags); // Add first button
horizSizer->Add(new wxButton(this, 124,"Abort"), ButtonFlags); // Add second button
horizSizer->Add(new wxButton(this, 125,"Ignore"), ButtonFlags); // Add third button
vertSizer->Add(horizSizer); // Add child sizer to parent sizer
SetSizerAndFit(vertSizer);
}

Answer 1

This happens because you didn't tell your main sizer (vertSizer) to grow the horizSizer to fill all the available space, you need to add wxSizerFlags().Expand() to the one but last line to fix this.
Additionally, using ButtonFlags.Expand().Center() doesn't make sense: you can either expand or centre, but not both at once, so choose one. Finally, DoubleBorder() is preferable to Border(wxALL, 10).