Bug: Empty day trailing day with a different first weekday
If the first weekday is Monday the Sunday of the next month will by empty.
February

Yellow square is the day of the next month. Why is it highlighted? It is a different month.
March


April

I can duplicate this when setting the first day of the week to Monday.

This appears to be the case with any month where the first day is Monday.
_getCalendar function: insert the snippet after line 82 and check it out
if ($fd) {
$day0 += [datetime]$currentDay
}
Also, small optimization for block of 118-148 lines
$underline = 4 #$abbreviated[0].Length + 1 (3 or 4)
$days = [System.Collections.Generic.List[string]]::new()
$addday = {
$d = $abbreviated[$args[0]].padleft($underline, " ")
if ($NoANSI) {
$days.add($d)
} else {
$days.add(("{0}{1}{2}" -f $PScalendarConfiguration.DayofWeek, $d, "$esc[0m"))
}
}
$n = if ($fd -eq 0) {0} else {1}
for ($n; $n -lt $abbreviated.count; $n++) {. $addday $n}
if ($fd) {. $addday 0}
$underline usage:
line 176: $value = $d.tostring().padleft($underline, ' ')
line 197: [int]$pad = (10*$underline - $plainhead.Length) / 2 + 1
Thanks for the suggestions. Fixed the missing day problem. Working on other issues for the next release.
Added in v2.9.0