FIX: Session expired exception was thrown after reopening a screen

frontend-html/src/model/entities/DataSource.ts

@@ -51,4 +51,8 @@ export class DataSource implements IDataSource {
   getFieldByIndex(index: number): IDataSourceField | undefined {
     return this.fields.find(field => field.index === index);
   }
+
+  dispose(){
+    this.rowState.dispose();
+  }
 }

frontend-html/src/model/entities/FormScreen.ts

@@ -251,8 +251,13 @@ export class FormScreen implements IFormScreen {
     console.log("End of View bindings");
     console.log("");
   }
-
   /* eslint-enable no-console */
+
+  dispose(){
+    for (let dataSource of this.dataSources) {
+      dataSource.dispose();
+    }
+  }
 }
 
 export class FormScreenEnvelope implements IFormScreenEnvelope {

frontend-html/src/model/entities/RowState.ts

@@ -40,12 +40,13 @@ export class RowState implements IRowState {
   $type_IRowState: 1 = 1;
   suppressWorkingStatus: boolean = false;
   dataViewVisibleRows: Map<string,string[]> = new Map();
+  disposers: (()=> void)[] = [];
 
   constructor(debouncingDelayMilliseconds?: number) {
     this.triggerLoadDebounced = _.debounce(
       this.triggerLoadImm,
       debouncingDelayMilliseconds == undefined ? 0 : debouncingDelayMilliseconds);
-    visibleRowsChanged.subscribe((visibleRows) => {
+    const disposer = visibleRowsChanged.subscribe((visibleRows) => {
       const dataSource = getDataSource(this);
       if (!visibleRows || dataSource.identifier !== visibleRows.dataSourceId) {
         return;
@@ -59,6 +60,7 @@ export class RowState implements IRowState {
         this.triggerLoadDebounced();
       }
     });
+    this.disposers.push(disposer);
   }
 
   monitor: FlowBusyMonitor = new FlowBusyMonitor();
@@ -257,6 +259,10 @@ export class RowState implements IRowState {
     // TODO: Wait when something is currently loading.
   }
 
+  dispose(){
+    this.disposers.forEach(x => x());
+  }
+
   parent?: any;
 }
 

frontend-html/src/model/entities/WorkbenchLifecycle/WorkbenchLifecycle.ts

@@ -386,6 +386,7 @@ export class WorkbenchLifecycle implements IWorkbenchLifecycle {
     const api = getApi(this);
     if (openedScreen.content) {
       if (openedScreen.content.formScreen) {
+        openedScreen.content.formScreen.dispose();
         yield api.destroyUI({FormSessionId: getSessionId(openedScreen.content.formScreen)});
       } else if (openedScreen.content.preloadedSessionId) {
         yield api.destroyUI({FormSessionId: openedScreen.content.preloadedSessionId});

frontend-html/src/model/entities/types/IDataSource.ts

@@ -37,6 +37,8 @@ export interface IDataSource extends IDataSourceData {
   getFieldByIndex(idex: number): IDataSourceField | undefined;
 
   parent?: any;
+
+  dispose(): void;
 }
 
 export const isIDataSource = (o: any): o is IDataSource => o.$type_IDataSource;

frontend-html/src/model/entities/types/IFormScreen.ts

@@ -184,6 +184,8 @@ export interface IFormScreen extends IFormScreenData {
   printMasterDetailTree(): void;
 
   parent?: any;
+
+  dispose(): void;
 }
 
 export interface IScreenNotification {

frontend-html/src/model/entities/types/IRowState.ts

@@ -41,6 +41,8 @@ export interface IRowState extends IRowStateData {
   reload(): void;
 
   parent?: any;
+
+  dispose(): void;
 }
 
 export interface IRowStateItem {