\usepackage[]{todonotes}

\newcounter{ubcomment}
\newcommand{\ubcomment}[2][]{%
\refstepcounter{ubcomment}%
{%
\todo[linecolor=black,backgroundcolor={green!40!},size=\footnotesize]{%
\textbf{Fixme: UB [\uppercase{#1}\theubcomment]:}~#2}%
}}
\newcommand{\ubcommentinline}[2][]{%
\refstepcounter{ubcomment}%
{%
\todo[linecolor=black,inline,backgroundcolor={green!40!},size=\footnotesize]{%
\textbf{Fixme: UB [\uppercase{#1}\theubcomment]:}~#2}%
}}

\newcommand{\ubcommentmultiline}[2]{%
\refstepcounter{ubcomment}%
{%
\todo[linecolor=black,inline,caption={\textbf{{Fixme: UB}
    [\theubcomment] #1}} ,backgroundcolor={green!40!},size=\footnotesize]{%
\textbf{Fixme: UB [\theubcomment]:}~#2}%
}}

% add support for todo in equations
%\usepackage{marginnote}
%\makeatletter
%\renewcommand{\@todonotes@drawMarginNoteWithLine}{%
%\begin{tikzpicture}[remember picture, overlay, baseline=-0.75ex]%
%    \node [coordinate] (inText) {};%
%\end{tikzpicture}%
%\marginnote[{% Draw note in left margin
%    \@todonotes@drawMarginNote%
%    \@todonotes@drawLineToLeftMargin%
%}]{% Draw note in right margin
%    \@todonotes@drawMarginNote%
%    \@todonotes@drawLineToRightMargin%
%}%
%}
%\makeatother