Fancytooltips changes line spacing in beamer

Question

I try to show the bibliographic entry in a popup when the mouse pointer is over the citation key. To achieve this, I use the code from Audrey's answer. In the beamer class, this results in some line spacing issue: When supercite is used extra vertical space is added between the current and the upper line as the picture illustrates. In the first line of using just \textsuperscript everything works normal but in the second line when \textsuperscriptand \tooltip is used in combination the line spacing changes.

So, I reduced the problem down to this MWE, but don't know what to do now.

% --- tooltip document
\begin{filecontents*}{fancytipmark.tex}
\documentclass{article}
\usepackage[createtips]{fancytooltips}
\usepackage{geometry}
\geometry{noheadfoot,nomarginpar,margin=0in,paperwidth=4in,paperheight=1in}
\pagestyle{empty}
\parindent=0pt
\begin{document}
\keytip{citekey} abc
\end{document}
\end{filecontents*}

% --- presentation document
\documentclass[8pt]{beamer}
\usepackage[filename=fancytipmark, mouseover, movetips]{fancytooltips}
\begin{document}
Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua.\textsuperscript{1}

Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua.\textsuperscript{\tooltip{1}{citekey}}
\end{document}

Answer 1

You can use \smash:

% --- tooltip document
\begin{filecontents*}{fancytipmark.tex}
\documentclass{article}
\usepackage[createtips]{fancytooltips}
\usepackage{geometry}
\geometry{noheadfoot,nomarginpar,margin=0in,paperwidth=4in,paperheight=1in}
\pagestyle{empty}
\parindent=0pt
\begin{document}
\keytip{citekey} abc
\end{document}
\end{filecontents*}

% --- presentation document
\documentclass[8pt]{beamer}
\usepackage[filename=fancytipmark, mouseover, movetips]{fancytooltips}
\begin{document}

\begin{frame}
Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua.\textsuperscript{1}

Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua.\textsuperscript{\smash{\tooltip{1}{citekey}}}
\end{frame}
\end{document}