renamed panel titles in gtable of plot with facet_grid() (#3979)

Author: fabern

R/facet-grid-.r

@@ -338,7 +338,7 @@ FacetGrid <- ggproto("FacetGrid", Facet,
 
     panel_table <- gtable_matrix("layout", panel_table,
       panel_widths, panel_heights, respect = respect, clip = coord$clip, z = matrix(1, ncol = ncol, nrow = nrow))
-    panel_table$layout$name <- paste0('panel-', rep(seq_len(ncol), nrow), '-', rep(seq_len(nrow), each = ncol))
+    panel_table$layout$name <- paste0('panel-', rep(seq_len(nrow), ncol), '-', rep(seq_len(ncol), each = nrow))
 
     panel_table <- gtable_add_col_space(panel_table,
       theme$panel.spacing.x %||% theme$panel.spacing)