I updated to high Sierra and now 1.0.6 doesn't run well
1.0.6 is an ancient version - 1.0.x is no longer being updated.
However, it still happens with the latest version as well. See github issue: Menu don't show up in OSX High Sierra Menubar · Issue #6548 · arduino/Arduino · GitHub
The developers are investigating this, so it will probably be fixed in a future release, but I don’t see much chance of a fix in the 1.0.x branch.
Unfortunately, Apple does not value backwards compatibility with application software.