Platform: OS X scrollbars: correctly laying out in presence of 'always-show' scrollbars
IDEA-123688 Scrollbars do not scroll to the end of the viewport (a few symbols are not visible)
IDEA-126017 SQL: completion for varchar2
Make FileLocalStringEnumerator to occupy less memory for stub being loaded:
 - no need for String -> int mapping (it is needed for string enumeration during save)
 - use precalculated list size
reduce memory pressure for indices with keys unique for indexed file (e.g. something calculated for particular file): save value once it is calculated, no need to accumulate the value in appenders because it can not be scattered