Comment 1 for bug 1187128

Thanks for reporting this bug Dubstar.
What version of the toolkit are you using? It would be indicated by apt-cache policy qtdeclarative5-ubuntu-ui-toolkit-plugin

__iconWidth and __iconHeight were not supposed to be there and were deprecated a month ago. The icon size is constrained automatically to the height of the list item. This naive approach breaks for you since you have variable heights for the list items.