Merge branch 'develop' of https://github.com/ONLYOFFICE/sdkjs into develop

cell/model/Serialize.js

@@ -6034,14 +6034,14 @@
                         oTo.BestFit = oFrom.BestFit;
                     oTo.setHidden(oFrom.hd);
                     if(null != oFrom.xfs)
-                        oTo.xfs = oFrom.xfs.clone();
+                        oTo.setStyle(oFrom.xfs);
                     else if(null != oFrom.xfsid)
                     {
                         var xfs = oThis.aCellXfs[oFrom.xfsid];
                         if(null != xfs)
                         {
                             oFrom.xfs = xfs;
-                            oTo.xfs = xfs.clone();
+                            oTo.setStyle(xfs);
                         }
                     }
                     if(null != oFrom.width)

cell/model/Workbook.js

@@ -6192,7 +6192,7 @@
 		}
 	};
 	Cell.prototype.setStyleInternal = function(xfs) {
-		this.xfs = xfs;
+		this.xfs = g_StyleCache.addXf(xfs);
 		this._hasChanged = true;
 	};
 	Cell.prototype.getFormula=function(){

cell/model/WorkbookElems.js

@@ -2805,7 +2805,7 @@ StyleManager.prototype =
 		return this.xfs.list.length;
 	};
 	StyleCache.prototype._add = function(container, newVal) {
-		if (undefined === newVal.getIndexNumber()) {
+		if (newVal && undefined === newVal.getIndexNumber()) {
 			var hash = newVal.getHash();
 			var res = container.vals[hash];
 			if (!res) {
@@ -3211,25 +3211,14 @@ Col.prototype =
 	setStyle : function(xfs)
 	{
 		var oldVal = this.xfs;
-		var newVal = null;
-		this.xfs = null;
-		if(null != xfs)
-		{
-			this.xfs = xfs.clone();
-			newVal = xfs;
-		}
-		if(History.Is_On() && false == ((null == oldVal && null == newVal) || (null != oldVal && null != newVal && true == oldVal.isEqual(newVal))))
-		{
-			if(null != oldVal)
-				oldVal = oldVal.clone();
-			if(null != newVal)
-				newVal = newVal.clone();
-			History.Add(AscCommonExcel.g_oUndoRedoCol, AscCH.historyitem_RowCol_SetStyle, this.ws.getId(), this._getUpdateRange(), new UndoRedoData_IndexSimpleProp(this.index, false, oldVal, newVal));
+		this.setStyleInternal(xfs);
+		if (History.Is_On() && oldVal !== this.xfs) {
+			History.Add(AscCommonExcel.g_oUndoRedoCol, AscCH.historyitem_RowCol_SetStyle, this.ws.getId(), this._getUpdateRange(), new UndoRedoData_IndexSimpleProp(this.index, false, oldVal, this.xfs));
 		}
 	},
 	setStyleInternal : function(xfs)
 	{
-		this.xfs = xfs;
+		this.xfs = g_StyleCache.addXf(xfs);
 	},
 	setCellStyle : function(val)
 	{
@@ -3524,15 +3513,14 @@ Row.prototype =
 	setStyle : function(xfs)
 	{
 		var oldVal = this.xfs;
-		this.xfs = xfs;
-		this._hasChanged = true;
-		if (History.Is_On() && oldVal != this.xfs) {
+		this.setStyleInternal(xfs);
+		if (History.Is_On() && oldVal !== this.xfs) {
 			History.Add(AscCommonExcel.g_oUndoRedoRow, AscCH.historyitem_RowCol_SetStyle, this.ws.getId(), this._getUpdateRange(), new UndoRedoData_IndexSimpleProp(this.index, true, oldVal, this.xfs));
 		}
 	},
 	setStyleInternal : function(xfs)
 	{
-		this.xfs = xfs;
+		this.xfs = g_StyleCache.addXf(xfs);
 		this._hasChanged = true;
 	},
 	setCellStyle : function(val)