Fix #948: Cannot scroll down the window in calendar view

[yarrumevets]

Related issue

Closes #948

Context / Background

Horizontal scrolling features locks vertical scrolling in the calendar view, even when horizontal scrolling is not necessary/possible. This creates an unintuitive scroll lock.

What change is being introduced by this PR?

• How did you approach this problem?
  I looked into the mechanism that was blocking vertical scrolling to see how it was blocked, and what could be done to unblock it under conditions where it wasn't appropriate.

• What changes did you make to achieve the goal?
  I wrapped the logic that changes vertical scrolling to horizontal scrolling in a condition that limited this to only cases where the element in question had enough data ( more than the default 5 child elements ). re-enables vertical scrolling over the row once scrolling has reached the end in the horizontal direction.

• What are the indirect and direct consequences of the change?
  Direct consequences: You can now scroll vertically while hovering the cursor on any element that is not a row with excess data. These rows still maintain their horizontal scrolling functionality as before.
  There are no apparent indirect consequences.

How will this be tested?

Open the app in month view.
Make sure you have at least one row that has enough data to necessitate sideways scrolling.

• Fill in all the times with random data, and then use the + button to add even more times.
  Place the cursor over empty rows and check that vertical scrolling works.
  Place the cursor over a row with extra (off-screen) data and check that horizontal scrolling still works, allowing you to still access all data in that row.

Updated screen recording 👇

time-to-leave-no-scroll.mov

[tupaschoal]

I like how this improves the current solution, but I don't like the fact that it is being tied to the number of cells. If the user resizes down the app window such that they need horizontal scrolling even with 5 or less entries, they won't be able anymore.

I think based on my comment on the original issue:

switch to horizontal scrolling, but if it reaches the edges of horizontal scrolling (leftmost or rightmost scroll position) then start scrolling vertically.

This one is a better solution. I've tested and I think it works smoothly, let me know what you think

const currentScroll = this.scrollLeft;
this.scrollLeft -= (delta * 30);
if (currentScroll != this.scrollLeft)
{
    e.preventDefault()
}

(scrollLeft stops getting updated when it gets to the bounds, which are 0 and a given max value)

[yarrumevets]

Yeah, that makes total sense.
I've tested it with your solution and it seems to work quite nicely 👌

I've pushed the code changes and updated the PR, including the screen capture.

[tupaschoal]

\changelog-update
Message: Enhancement [#948]: Allow vertical scroll when horizontal scroll reaches edges on month view