Windows 10, Delphi 10.1 Berlin & the latest NG components.
If I use just the standard Buttons and double-click on the component on the form it puts up the designer without issue.
If I now add a custom button, either in the designer and close it, or in the Object Inspector, then double click on the component to re-open it, I get an access violation error in rtl240.bpl.
If I remove the custom button all is good again.
Is it just me or is this an issue?