Unable to adjust the length of tracks' title region.

[Han-26]

Hello,
I use Gviz to plot tracks but it can't show the title completely and the title region is too wide.
I couldn't find any parameters to adjust the length of title regions or the coordinate of titles.
Could you please help me to solve this?

chr=unique(t_gene_methP$chr)
  start=min(t_gene_methP$start)
  end=max(t_gene_methP$end)
  cpgI=GRanges(seqnames = Rle(t_gene_methP$chr),ranges = IRanges(start=t_gene_methP$start,end=t_gene_methP$end),betas=t_gene_methP[,4:ncol(t_gene_methP)])
  iTrack <- IdeogramTrack(chromosome = chr,genome = "hg38",col="red",fontsize=10)
  gTrack <- GenomeAxisTrack(range = cpgI,fontsize=6,exponent = 1)
  aTrack <- AnnotationTrack(cpgI, name = "CpG",background.title = "#FFFEDB",fill="orange",just.group="right")
  dTrack_box<-DataTrack(range = cpgI,genome = "hg38",chromosome = chr,name = "DNA Methylation",
                        groups=factor(cGrp),missingAsZero=F,na.rm=T,
                        type=c("boxplot"),col=c("light blue","light green",'light pink'),
                        box.width=10,box.ratio=0.5,cex.legend=0.5,cex=0.2
  )
  
  #plot
  plotTracks(list(iTrack,gTrack,dTrack_box,aTrack,grtrack),sizes = c(0.3,0.5,1.5,0.2,0.5),
             extend.right = 10,extend.left = 10,main = paste0(geneN," on RRBS"),cex.main = 1,
             margin = 1,lwd.border.title=0.2,
             collapseTranscripts = TRUE,
             #labelPos = "below",
             showTitle = TRUE,
             from = start,to = end