NavbarDropDownButton with bootstrap-4 incorrectly show

[bochkov-vi]

NavbarDropdownButton incorrectly renders button with attribute type="button"
its add border around of component and remove background color
to fix i need

.. new NavbarDropDownButton(...) {
      ....
        }.addToButton(new AttributeModifier("type",AttributeModifier.VALUELESS_ATTRIBUTE_REMOVE))....

[martin-g]

Please give some more information. It is nearly impossible to find out what should be fixed from this short description and code snippet.

[bochkov-vi]

i use maven dependency
<wicket-bootstrap.version>3.0.0-M8</wicket-bootstrap.version>

NavbarDropDownButton extends DropDownButton
where in markup file
... <a class="dropdown-toggle" wicket:id="btn" type="button"
data-toggle="dropdown" aria-haspopup="true" href="javascript:;" aria-expanded="false">
...
type="button" makes NavbarDropDownButton show border and lost backgraund color

[bochkov-vi]

I think it is necessary to make the "type" attribute customizable for baseButton
in DropDownButton class
when NavbarDropDownButton exending, remove it value from markup when initilizing