I started using HeidiSQL a few months ago and I enjoy it.
I have some minor suggestions to make. If I run a query like "SELECT COUNT(*) FROM table WHERE value = 'one & two';" and then I place the mouse over the tab, the ampersand is displayed incorrectly like _ (probably it should be doubled like && to be displayed correctly).
I often comment multiple lines of queries with a # at the beginning of the line, because I don't want to lose them and I uncomment them as I need. After I run all uncommented queries, the mouse over query tabs shows all the commented queries from above as well as the valid query. Is there a way to display just the relevant query? I suggest for example not to display the lines that start with # and display the comments that are in between / ... /