Tikzposter combining title only blocks and offset on the next block

Question

Some time ago now, I answered this question Tikzposter block with no content And I thought all was nice and good.

But after having had to use the command I created I realized that around 2cm of blank space is inserted in after any titleblock. This can bee fixed with the titleoffsety=2cm and bodyoffsety=2cm on any top block right below the title block. To streamline this I could make an aftertitleblock that adds this, but it seems like a dirty macro if I need to make a new macro to clean after myself.

So I was wondering if there was a way to remove the 2cm of emptyness, from within the defineblockstyle command.

MWE:

\documentclass{tikzposter}
\defineblockstyle{Justtitle}{
        }{
        \ifBlockHasTitle
                \draw[color=framecolor, fill=blocktitlebgcolor,
                rounded corners=\blockroundedcorners] (blocktitle.south west)
                rectangle (blocktitle.north east);
        \fi
}
\newcommand{\titleblock}[1]{\useblockstyle{Justtitle}\block{#1}{}\useblockstyle{Default}}

\begin{document}
\titleblock{Cool title}
\begin{columns}
        \column{0.5}
        \block[titleoffsety=2cm,bodyoffsety=2cm]{cool block title}{block text} %NOTE THE OFFSET
        \block{next block}{more text}
        \column{0.5}
        \block{even cooler, but wrongly placed title}{Super cool text here}%NOTE THE LACK OF OFFSET
        \block{hello}{duck}
\end{columns}
\end{document}

Produces:

Answer 1

When tikzposter calculates the height of the body of a block, it does

\setlength{\TP@blockbodyheight}{\ht\TP@blockbodybox + \dp\TP@blockbodybox +2\TP@blockbodyinnersep}

As you can see two times the blockbodyinnersep is added to the height. You can make use of that fact and set the bodyinnersep in your \titleblock macro to an appropriate negative length:

\newcommand{\titleblock}[1]{\useblockstyle{Justtitle}\block[bodyinnersep=-4mm]{#1}{}\useblockstyle{Default}}

Complete example:

\documentclass{tikzposter}
\defineblockstyle{Justtitle}{
        }{
        \ifBlockHasTitle
                \draw[color=framecolor, fill=blocktitlebgcolor,
                rounded corners=\blockroundedcorners] (blocktitle.south west)
                rectangle (blocktitle.north east);
        \fi
}
\newcommand{\titleblock}[1]{\useblockstyle{Justtitle}\block[bodyinnersep=-4mm]{#1}{}\useblockstyle{Default}}

\begin{document}
\titleblock{Cool title}
\begin{columns}
        \column{0.5}
        \block{cool block title}{block text} 
        \block{next block}{more text}
        \column{0.5}
        \block{even cooler, but wrongly placed title}{Super cool text here}
        \block{hello}{duck}
\end{columns}
\end{document}