I created a small workaround - it was enough for me to remove the overflow from the tab container after adding all the tabs.
for (int i = 0; i < tabLayout.getWidgetCount(); i++) {
final Widget widget = tabLayout.getWidget(i);
DOM.setStyleAttribute(widget.getElement(), "position", "relative");
final Element parent = DOM.getParent(widget.getElement());
DOM.setStyleAttribute(parent, "overflowX", "visible");
DOM.setStyleAttribute(parent, "overflowY", "visible");
}
PS: PX TabLayoutPanel IE, .
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