First off, thanks for a great piece of software!
There are two features I want to suggest that I would find very useful:
The ability to enter simple expressions in “amount” input boxes. It can be really simple like 0.312.50 or 76.32+41.88 (just the operators ±/ and perhaps () should suffice). This is great for example when you have to assign only 30% of an expense for professional use, or if you need to calculate an amount inclusive/exclusive of tax based on the other amount that you know.
The ability to “duplicate” an entry, giving you the same screen as “Update” would, but then creating a new entry when you’re done, which is useful for (nearly or totally) repetitive transactions, where you’ve got e.g. the same split of accounts and description but perhaps with different amounts every month.
I am a software developer so I can help with the implementation if needed