How to set the position of groups in a Seurat object on a FeatureHeatmap plot
I don't think this is possible in Seurat v2, but in v3 you can change the factor levels of the grouping variable to change the plot order:

library(Seurat)

FeaturePlot(object = pbmc_small,
            features = head(VariableFeatures(pbmc_small), 2),
            split.by = 'groups')




Change the order:

pbmc_small$groups &lt;- factor(pbmc_small$groups, levels = c('g2', 'g1'))

FeaturePlot(object = pbmc_small,
            features = head(VariableFeatures(pbmc_small), 2),
            split.by = 'groups')