Decouple removal of independent time context for a view from refreshing context for other views (#6334)

* Decouple removing the context for a view from refreshing the context of views to get their upstream contexts

* Add test for clicking on an item in the elements pool for a preview

* Add test to ensure independent time context for items with no parents works as expected

e2e/tests/functional/plugins/plot/overlayPlot.e2e.spec.js

@@ -140,4 +140,61 @@ test.describe('Overlay Plot', () => {
         expect(yAxis3Group.getByRole('listitem', { name: swgB.name })).toBeTruthy();
         expect(yAxis3Group.getByRole('listitem').nth(0).getByText(swgB.name)).toBeTruthy();
     });
+
+    test('Clicking on an item in the elements pool brings up the plot preview with data points', async ({ page }) => {
+        const overlayPlot = await createDomainObjectWithDefaults(page, {
+            type: "Overlay Plot"
+        });
+
+        const swgA = await createDomainObjectWithDefaults(page, {
+            type: "Sine Wave Generator",
+            parent: overlayPlot.uuid
+        });
+
+        await page.goto(overlayPlot.url);
+        await page.click('button[title="Edit"]');
+
+        await page.locator(`#inspector-elements-tree >> text=${swgA.name}`).click();
+        await page.locator('.js-overlay canvas').nth(1);
+        const plotPixelSize = await getCanvasPixelsWithData(page);
+        expect(plotPixelSize).toBeGreaterThan(0);
+    });
 });
+
+/**
+ * @param {import('@playwright/test').Page} page
+ */
+async function getCanvasPixelsWithData(page) {
+    const getTelemValuePromise = new Promise(resolve => page.exposeFunction('getCanvasValue', resolve));
+
+    await page.evaluate(() => {
+        // The document canvas is where the plot points and lines are drawn.
+        // The only way to access the canvas is using document (using page.evaluate)
+        let data;
+        let canvas;
+        let ctx;
+        canvas = document.querySelector('.js-overlay canvas');
+        ctx = canvas.getContext('2d');
+        data = ctx.getImageData(0, 0, canvas.width, canvas.height).data;
+        const imageDataValues = Object.values(data);
+        let plotPixels = [];
+        // Each pixel consists of four values within the ImageData.data array. The for loop iterates by multiples of four.
+        // The values associated with each pixel are R (red), G (green), B (blue), and A (alpha), in that order.
+        for (let i = 0; i < imageDataValues.length;) {
+            if (imageDataValues[i] > 0) {
+                plotPixels.push({
+                    startIndex: i,
+                    endIndex: i + 3,
+                    value: `rgb(${imageDataValues[i]}, ${imageDataValues[i + 1]}, ${imageDataValues[i + 2]}, ${imageDataValues[i + 3]})`
+                });
+            }
+
+            i = i + 4;
+
+        }
+
+        window.getCanvasValue(plotPixels.length);
+    });
+
+    return getTelemValuePromise;
+}