All new editor windows are now docked in the tab from which they were summoned. Existing editor window positions are remembered.
When opening materials, textures and meshes the tab that opens will randomly either dock to the main editor window or open as its own window.
User's video highlights inconsistency.
1. Open UE4 Editor
2. Create a project in 4.6.1 (with starter content)
3. Copy project to 4.7 preview
4. Open project in 4.7
5. Double click assets (meshes/materials/etc) to open their editor window.
Result:
Some assets open in their own window while others dock to the main viewport.
Head over to the existing Questions & Answers thread and let us know what's up.