I was using the upcoming events widget to display events from a single category and and it just did not work. I searched the support forum and nobody have reported any issues regarding category trouble in upcoming widgets. So I did some debugging and found a simple bug in the code.
my-calendar-limits.php, line 10
if ( $category == 'all' || strpos( $category, "all" ) !== false ) {
if the category is 'Football' or 'Baseball' or any other word with 'ball' as a substring, the condition will pass while it should not.
this is how I fixed it.
if ( preg_match('/^all$|^all,|,all$|,all,/i', $category) > 0 ) {
