I recently switched to LXQT from KDE and I have realized that some windows don't have minimize buttons. They all have rollup, unroll buttons which shrink the form to the size of the titlebar only and restore it when unrolled.
Without minimize buttons

With minimize buttons.

Is there something about the forms themselves that result in LXQT not showing the minimize button or are some configuration settings required in LXQT itself for minimize buttons to be displayed on all the applicable forms?