Chart: tooltip background should be displayed on point hover when using an asynchronous content template (T1244092) (#29435)

Author: EugeniyKiyashko

packages/devextreme/js/viz/core/plaque.js

@@ -314,7 +314,7 @@ export class Plaque {
         if(this.contentTemplate.render) {
             this.contentTemplate.render({ model: options, container: this._contentGroup.element, onRendered: onRender });
         } else {
-            return this.contentTemplate({ group: this._contentGroup, onRender, ...restProps });
+            this.contentTemplate({ group: this._contentGroup, onRender, ...restProps });
         }
         return true;
     }

packages/devextreme/testing/tests/DevExpress.viz.core/tooltip.tests.js

@@ -1208,7 +1208,7 @@ QUnit.test('Show. W/o params. Template', function(assert) {
     // act
     const result = this.tooltip.show(formatObject, { x: 100, y: 200, offset: 300 }, eventData, undefined, callback);
 
-    assert.strictEqual(result, undefined);
+    assert.strictEqual(result, true);
     assert.deepEqual(this.eventTrigger.lastCall.args, ['tooltipShown', eventData], 'event is triggered');
 
     assert.deepEqual(this.tooltip._state, {
@@ -1416,7 +1416,7 @@ QUnit.test('Call template if empty text', function(assert) {
     // act
     const result = this.tooltip.show(formatObject, { x: 100, y: 200, offset: 300 }, eventData, undefined, callback);
 
-    assert.strictEqual(result, undefined);
+    assert.strictEqual(result, true);
     assert.deepEqual(this.eventTrigger.lastCall.args, ['tooltipShown', eventData], 'event is triggered');
 
     assert.equal(this.options.contentTemplate.callCount, 1);