"trajectories must be concatenated without having double frames.[PAR]",
"Option [TT]-dump[tt] can be used to extract a frame at or near",
- "one specific time from your trajectory.[PAR]",
+ "one specific time from your trajectory, but only works reliably",
+ "if the time interval between frames is uniform.[PAR]",
"Option [TT]-drop[tt] reads an [REF].xvg[ref] file with times and values.",
"When options [TT]-dropunder[tt] and/or [TT]-dropover[tt] are set,",