Recently, LibreOffice 4.0 was released, introducing new features and a solid set of improvements, optimizations and enhancements.
Yet, it seems that presently the LibreOffice developers are working on porting LibreOffice's fixed-size dialogs to optimized dialogs created with Glade.
Among the decisions behind the transition are inexistent visual editor for dialogs, inability to create mockups without supporting code, manual code implementation for actions like hiding widgets, visual wasted space with hassle-full dialog resizing, etc.