I believe this is by design. However, the Flowcharts are only contained like this if they are inside of a sequence (the standard Workflow has a high level sequence above it). If you add a full Flowchart type workflow to the project, it will be viewable in full screen:
I had a similar issue after a Studio version upgrade. You can try a few things:
Check the zoom level of the Flowchart and zoom out/in using Ctrl + Mouse Wheel.
Try using Fit to Screen from the Flowchart designer toolbar if available.
Reset the Studio layout from Home → Settings → General → Reset Settings if the designer layout itself looks abnormal.
Also check the Windows display scaling (100%, 125%, etc.), as this can affect how much of the designer is visible.
Since this started specifically after upgrading from 2022.10 to 2025.10.16, it may also be worth checking whether the behavior is related to the newer Studio designer UI.
If you can share a screenshot of how the Flowchart looks in 2025.10.16, it would be easier to identify whether it’s a zoom issue or a layout/display issue.