In other themes (inherited from base), panel has styles
.#{$primary-stylename}.v-has-width > .#{$primary-stylename}-content {
width: 100%;
}
.#{$primary-stylename}.v-has-height > .#{$primary-stylename}-content {
height: 100%;
}
But in Valo:
.#{$primary-stylename}-content {
@include box-sizing(border-box);
width: 100%;
height: 100%;
@include valo-panel-adjust-content-margins;
}
It leads to unnecessary scrollbars in case of -1px height of panel content.
http://dev.vaadin.com/attachment/ticket/15479
