cdcab26 removed excessive clearing of the windows. But it caused the
problem where the right side of the preview window border was not
cleared when hiding the preview window with the scrollbar disabled.
De-duplicate code and reduce the amount of code that has to be changed
when new BorderShapes are being added. This also adds and uses the
missing HasBottom().
When the chosen preview border shape has no left and/or right border,
the minimum total preview window size decreases. But due to the
hardcoded value for the minimum size of the preview window the size
could not be decreased further than 5.
The minimum window height decreases when no extra line for the
horizontal separator is used (e.g. with `--info=inline --no-separator`).
In this case the preview window should be able to occupy this extra
line.
Enable resizing the preview window by dragging its border with the
mouse. This works with all border styles except for `none`.
Counter-intuitively, having the border only on the opposite side of the
window works too - dragging from it will first decrease the preview size
to its minimum.
We cache a merger for partial input as well, because it is automatically
invalidated as soon as the new data comes in.
However, there was a race condition where a cached merger for a partial
input is used even after the input stream was complete. This commit
fixes the problem.
Fix#4034
Only requiring '-suffix in --exact mode is confusing and not
straightforward. Requiring '-prefix in --exact mode means that
the users can experience unintended mode switches while typing.
e.g.
'it -> fuzzy (many results)
'it' -> boundary (few results)
'it's -> fuzzy (many results)
However, user who intends to input a boundary query should not be
interested in the intermediate results, and the number of matches
decreases as she types, so it should be okay.
On the other hand, user who does intend to type "it's" will be surprised
by the sudden decrease of the match count, but eventually get the right
result.
