[update] correct and complete docs for v5.2

Author: mafanya23

docs/api/spreadsheet_afterdataloaded_event.md

@@ -13,7 +13,7 @@ description: You can learn about the afterDataLoaded event in the documentation
 ### Usage
 
 ~~~jsx
-afterColumnAdd: (cell: string) => void;
+afterDataLoaded: () => void;
 ~~~
 
 ### Example

docs/migration.md

@@ -13,7 +13,6 @@ description: You can learn about migration in the documentation of the DHTMLX Ja
 In v5.2 the way of freezing/unfreezing columns and rows has been modified:
 
 - the `leftSplit` and `topSplit` configuration properties that have been used for fixing columns and rows were deprecated
-- new API methods `freezeCols()`, `unfreezeCols()`, `freezeRows()`, `unfreezeRows()` and a new action `toggleFreeze` were introduced
 
 ~~~jsx title="Before v5.2"
 const spreadsheet = new dhx.Spreadsheet("spreadsheet_container", {
@@ -22,6 +21,8 @@ const spreadsheet = new dhx.Spreadsheet("spreadsheet_container", {
 });
 ~~~
 
+- new API methods were introduced: [`freezeCols()`](api/spreadsheet_freezecols_method.md), [`unfreezeCols()`](api/spreadsheet_unfreezecols_method.md), [`freezeRows()`](api/spreadsheet_freezerows_method.md), [`unfreezeRows()`](api/spreadsheet_unfreezerows_method.md) 
+
 ~~~jsx title="From v5.2" 
 // for rows
 spreadsheet.freezeRows("B2"); // the rows up to the second row will be fixed
@@ -34,7 +35,11 @@ spreadsheet.freezeCols("B2"); // the columns up to the "B" column will be fixed
 spreadsheet.freezeCols("sheet2!B2"); // the columns up to the "B" column in "sheet2" will be fixed
 spreadsheet.unfreezeCols(); // fixed columns in the current sheet will be unfrozen
 spreadsheet.unfreezeCols("sheet2!A1"); // fixed columns in "sheet2" will be unfrozen
+~~~
+
+- new action was added: [`toggleFreeze`](api/overview/actions_overview.md/#list-of-actions) 
 
+~~~jsx title="From v5.2"
 // using the `toggleFreeze` action with the beforeAction/afterAction events
 spreadsheet.events.on("afterAction", (actionName, config) => {
     if (actionName === "toggleFreeze") {
@@ -49,6 +54,31 @@ spreadsheet.events.on("beforeAction", (actionName, config) => {
 });
 ~~~
 
+- new `freeze` property for the *sheets* object of the [`parse()`](api/spreadsheet_parse_method.md) method was added. It allows fixing rows and columns for particular sheets in the dataset, while parsing data into Spreadsheet: 
+
+~~~jsx {10-13} title="From v5.2"
+const data = {
+    sheets : [
+        { 
+            name: "sheet 1", 
+            id: "sheet_1",
+            data: [
+                { cell: "A1", value: "Country" },
+                { cell: "B1", value: "Product" }
+            ],
+            freeze: {
+                col: 2,
+                row: 2
+            },
+            // more sheet settings
+        }, 
+        // more sheets configuration objects
+    ]
+};
+
+spreadsheet.parse(data);
+~~~
+
 ## 4.3 -> 5.0
 
 In v5.0, the *"help"* option of the [toolbarBlocks](api/spreadsheet_toolbarblocks_config.md) property is renamed to *"helpers"*. Besides, the default set of options is extended by the new *"actions"* option.

docs/working_with_ssheet.md

@@ -111,6 +111,34 @@ spreadsheet.unfreezeRows(); // fixed rows in the current sheet will be unfrozen
 spreadsheet.unfreezeRows("sheet2!A1"); // fixed rows in "sheet2" will be unfrozen
 ~~~
 
+### Freezing rows/columns in the dataset
+
+You can also fix rows and columns for particular sheets in the dataset, while parsing data into Spreadsheet.
+For this, use the `freeze` property in the *sheets* object of the [`parse()`](api/spreadsheet_parse_method.md) method:
+
+~~~jsx {10-13}
+const data = {
+    sheets : [
+        { 
+            name: "sheet 1", 
+            id: "sheet_1",
+            data: [
+                { cell: "A1", value: "Country" },
+                { cell: "B1", value: "Product" }
+            ],
+            freeze: {
+                col: 2,
+                row: 2
+            },
+            // more sheet settings
+        }, 
+        // more sheets configuration objects
+    ]
+};
+
+spreadsheet.parse(data);
+~~~ 
+
 ## Hiding/showing rows and columns
 
 You can hide and show particular rows and columns via the corresponding API methods.