In Apache OO 3.4 the Quickstart pops up the AOO splash screen. This is a known bug and will be fixed for 3.4.1. If the Quickstart Autoload on startup is unchecked, Check it, exit OpenOffice and restart your computer (Power off, wait, then on). Now Uncheck your Autoload, exit OpenOffice and restart (Power off again). All should now be well, with no automatic splsh screen.
To be certain we are talking about the same thing, the sequence involved is
/Tools /Options /OpenOffice.org : Memory : OpenOffice Quickstarter : Enable Systray Quickstarter [Check or uncheck as required].
Apache OpenOffice 4.1.2 on Xubuntu 16.04 (mostly 64 bit version) and infrequently on Win2K/XP