fix frappe/erpnext#12112 (#4677)

frappe/public/js/frappe/form/grid.js

@@ -480,6 +480,8 @@ frappe.ui.form.Grid = Class.extend({
 	},
 
 	setup_visible_columns: function() {
+		if (this.visible_columns) return;
+
 		var total_colsize = 1,
 			fields = this.editable_fields || this.docfields;
 

frappe/public/js/legacy/form.js

@@ -197,7 +197,7 @@ _f.Frm.prototype.watch_model_updates = function() {
 		if(doc.name===me.docname) {
 			if ((value==='' || value===null) && !doc[value]) {
 				// both the incoming and outgoing values are falsy
-				// the texteditor, summernote, changes nulls to empty strings on render, 
+				// the texteditor, summernote, changes nulls to empty strings on render,
 				// so ignore those changes
 			} else {
 				me.dirty();
@@ -385,6 +385,8 @@ _f.Frm.prototype.refresh = function(docname) {
 			frappe.utils.scroll_to(0);
 			this.hide_print();
 		}
+		// reset visible columns, since column headings can change in different docs
+		this.grids.forEach(grid_obj => grid_obj.grid.visible_columns = null);
 		frappe.ui.form.close_grid_form();
 		this.docname = docname;
 	}