Hmm I like your plan. I submit to you that having a little checked icon or mark on the entry can be used alongside your plan and let a user know that they are in good standing up to that point. That check can also be used by a user that hand reconciles their account. You are correct that right click isn’t used much, but it’s being used more(google maps for example). You could put the user activation of the check on entry edit screen(along with a note about the right click) and as a right click option. its a one/two time learning experience that I think users will pick up on quickly. Plus from then on, you open up a whole new menu area for your use.
Oh, one little fly in the ointment. What if you have users who have constant amounts being taken out from multiple places? like writing allowance checks to your teenage kids as an example. if one of 3 checks for $50 clear CB(calendarbudget) may not know which one it was. I admit tho that this type of occurance will be rare, but anytime you have multiple bank entries that match you could mistakenly clear the wrong one. Perhaps you need to check for that when you parse the bank statement and alert the user. you could even go so far as to present them with a popup displaying the bank entry info in question and the multiple matching entries from the calendar and let them decipher and select the correct entry to reconcile. There’s a few extreme cases you’d have to test out for, but it could be done