In Extras -> Ansicht -> Optionen -> Symbolgröße On changing Symbolgröße to large nothing happens until I also change the Symbol theme. Also does not work the other way round if I want to change from large to small. Have to change theme again.
For en-US version: Tools -> Options -> View -> Icon size and style. The same issue occurs on Linux with Libo 3.5.2. Changing only the icon size has no effect. You have to change the theme as well, so the change in icon size get's applied.
*** This bug has been marked as a duplicate of bug 35972 ***