The new modal dialogs in GTK/gnome that are nailed to the parent window's center and can't be moved are such unintelligent design. Libreoffice now uses these for the paragraph style editing dialog so now you can't move the dialog anymore to look at the effect of your settings on the actual document. A similar issue happens with the "save as" dialog in many GTK applications. Often you'd want to look at the content of the document to decide on a file name.