We are using JSAPI 4.0 in our web application to display, amongst others, feature layers. We have set a PopupTemplate on the layers and upon clicking on the feature, the popup pops up as expected. However, if the browser window is maximized (or a maximized window is resized), the popup shifts its position sligthly in regards to the feature, so that the pointy tip of the popup no longer aligns with it. We did not observe this effect when resizing the window horizontally or vertically. Also, panning the map causes the popup to be re-drawn correctly. This is not a major issue, but we would like to know if there is something we can do about this.
Here is the popup before resizing:
And here it is after:
The issue can be reproduced with the sample code provided by ESRI: Get started with popups - 4.0