The fix for this issue has been released and is now available in Kodular Creator as of 2025.10.4.
The problem was caused by a change in Chrome 144 | Release notes | Chrome for Developers (released January 13, 2026) that altered how mouse events behave when page elements are repositioned. This change is part of a Chrome Platform Status and affects all Chromium-based browsers.
The flyout is the panel that opens when you click a block category (like Control, Logic, Math, etc.) in the Blocks editor, showing the available blocks you can drag into your workspace. When you hovered over a block in the flyout, the editor’s code was briefly moving the block in the page structure to bring it to the front. This was harmless before, but with the new Chrome behavior it causes a cascade of extra mouse events, resulting in multiple blocks appearing highlighted and drag-and-drop breaking entirely.
The fix skips that unnecessary repositioning for flyout blocks (since they don’t overlap and don’t need it), while keeping the visual highlight working normally. This has already been deployed, so drag-and-drop from the flyout should now work again in Chrome, Edge, Brave, Opera, and all other Chromium-based browsers.