This issue occurs when the dimensions of the ADM window do not match what is being shown on the screen due to screen resolution. As a result, when attempting to click on the close button, the cursor tries to resize the window.
To resolve this, you can do one of the following:
Change the resolution of the screen that ADM is being used on by Right clicking on the desktop and selecting Display Settings. Adjust the resolution to the highest resolution that isn't currently being used.
Please ensure that the scaling of the window is set to the default. If it is not set to default, it may cause this issue.
If using multiple monitors that have different resolutions, move the ADM window onto a different monitor. The window should now show correctly and allow you to close.
This could also be caused by the screen with Dimensions/ADM open not being the main display screen. This can be changed by selecting the screen in question in the Display setting and selecting 'Make this my main Display'
It is also worth try setting your text size to 100%.