The TradeStation Trading App Store was retired before 2022, yet TradeStation 9.5 continues to place an animated banner for it at the top of a screen, even though the store is no longer usable. It's unclear how to remove this permanently from the application's settings, aside from upgrading to a newer version of the platform. There is a simple way to remove it, though you'll need to do so each time you run the app.
You can use either of the following two methods to remove it. Both involve bringing up the active application windows.
The first is to use the Alt+Tab keyboard approach to show all active windows. A selection of application images will appear, each showing a snapshot of what that window contains. You'll see your various window contents appear in the windows - they're blacked out in the following example image, aside from the one that represents the TradeStation app store banner. If you have a lot of open windows, you may need to continue to click the Tab button while holding down the Alt key to cycle through the various window snapshots. Once you find the box shown at the bottom right of the following image - the one that that shows PopupWindow as its title - you can select the X in the red box that appears in the upper-right of that window. This will close that specific window, and the animated AppStore banner will go away.
Another way to achieve the same thing is to use the Task View button near the Start menu button in the Windows Task Bar. The keyboard shortcut for Task View is WindowsKey + Tab. In Windows 11, it's the white and gray squares button, as shown just left of the weather icon in the following image of taskbar items:
Click that button to get a similar view of all open windows on each screen. Locate the one you want to close, scrolling with your mouse wheel if you need to, and click its close button, and hit the ESC key or the Task View button to close out the task view.