gwtbootstrap3. How to justified ButtonGroup element with buttons

I would like to justified my button group to whole width of parent.

I am trying to Justified button groups

Here is my code:

ButtonGroup buttonGroupHelper = new ButtonGroup();

Button loginButton = new Button("Log in");
Button resetButton = new Button("Reset");
Button forgotCredentialsButton = new Button("Forgot credentials?");

buttonGroupHelper.add(loginButton);
buttonGroupHelper.add(resetButton);
buttonGroupHelper.add(forgotCredentialsButton);

And I am getting this:

When I will add this line:

buttonGroupHelper.setJustified(true);

I am getting this:

I use bootstrap css darkly theme.

Here is html that my gwtbootstrap3 framework produce:

<div class="btn-group btn-group-justified">
    <button type="button" class="btn btn-success"><i class="fa fa-play-circle-o"></i> Log in</button>
    <button type="button" class="btn btn-danger"><i class="fa fa-times-circle-o"></i> Reset</button>
    <button type="button" class="btn btn-warning"><i class="fa fa-key"></i> Forgot credentials?</button>
</div>

Am I doing something wrong. Or is this just a bug?

Please help.

You should put the buttons inside button groups and then put the button groups inside the helper button group.

ButtonGroup buttonGroupHelper = new ButtonGroup();
ButtonGroup loginBtnGroup = new ButtonGroup();
ButtonGroup resetBtnGroup = new ButtonGroup();
ButtonGroup forgotBtnGroup = new ButtonGroup();

Button loginButton = new Button("Log in");
Button resetButton = new Button("Reset");
Button forgotCredentialsButton = new Button("Forgot credentials?");

loginBtnGroup.add(loginButton);
resetBtnGroup.add(resetButton);
forgotBtnGroup.add(forgotCredentialsButton);

buttonGroupHelper.add(loginBtnGroup);
buttonGroupHelper.add(resetBtnGroup);
buttonGroupHelper.add(forgotBtnGroup);

buttonGroupHelper.setJustified(true);