Vertical scroll bar can be drawn without handle

[mattrunyon]

Description

If the table is sized just right, the vertical scroll track is drawn, but not the handle. This occurs if the last row of the table goes under the horizontal scroll bar. This is caused by the fix for #446, but it was broken previously too. The scroll bar just didn't appear at all (the bottom row is still obscured by the horizontal bar)

Steps to reproduce

1. Create a table with only a few rows such as this Python

from deephaven import new_table
from deephaven.column import string_col, char_col, int_col

table = new_table([
    string_col("Short", ["A" , "B", "C", "D"]),
    string_col("Long", ["A"*50 , "B"*500, "C"*5000, "D"*49900]),
    char_col("Char", "ABCD"),
    int_col("Int", [123456789, 234567890, 42, 8675309]),
])

2. Shrink to where the horizontal scroll bar appears.
3. Shrink vertically until the last row is just under the horizontal scroll bar.

Expected results

Both scroll bars fully appear

Actual results

Vertical scroll track appears, but not the handle

Versions

• Deephaven: 0.11.9