# problems plotting trancripts on same line

ensembl_transcript_id_A <- "ENST00000561401"
ensembl_transcript_id_B <- "ENST00000560818"

mart <- biomaRt::useMart(
  biomart = "ENSEMBL_MART_ENSEMBL",
  dataset = "hsapiens_gene_ensembl",
  host = "dec2013.archive.ensembl.org")

biomartBoth <- Gviz::BiomartGeneRegionTrack(
  filters = list(
    ensembl_transcript_id = c(ensembl_transcript_id_B,
                              ensembl_transcript_id_A)),
  biomart = mart)

# Create axis track
axisTrack <- Gviz::GenomeAxisTrack()

# works as expected:
Gviz::plotTracks(
  c(biomartBoth, axisTrack),
  from = biomartBoth@start,
  to = biomartBoth@end,
  chromosome = rep("chr15", 2),
  showId = TRUE,
  just.group = "below"
)
# plots the transcript on different lines:
Gviz::plotTracks(
  c(biomartBoth, axisTrack),
  from = biomartBoth@start,
  to = biomartBoth@end,
  chromosome = rep("chr15", 2),
  showId = TRUE,
  just.group = "below",
  reverseStrand = TRUE
)
# if I turn showId off, it works as expected again:
Gviz::plotTracks(
  c(biomartBoth, axisTrack),
  from = biomartBoth@start,
  to = biomartBoth@end,
  chromosome = rep("chr15", 2),
  showId = FALSE,
  just.group = "below",
  reverseStrand = TRUE
)