Unity developer +Marco Trevisan is working on some tweaks for Ubuntu 15.04 Vivid Vervet and among them, there's a fix for a three year old bug related to Unity's menus.
Marco's work involves adding an option to always show the Unity menus (in Unity, the menus are currently displayed on mouseover). Furthermore, this option will work with both the regular Appmenu / global menu, displayed on the top Unity panel, as well as LIM (locally integrated menus), displayed in the application titlebar:
In the current implementation, the option to always show the menu is available via Dconf-Editor (com > canonical > unity > always-show-menus) and I don't know if it will be integrated in System Settings, but I'm sure that applications like Unity Tweak Tool will get an option to make this easier to access and configure.
Here's what the "always-show-menus" key description says:
When this is enabled, the application menus will be always shown (on the window decoration or in the unity panel, depending whether integrated menus are enabled), otherwise they will be shown only when the mouse cursor is over the relative mouse area.