Troubleshooting / Bugs: Find/Replace

If I open the find dialog (Ctrl+F) and start typing in the Find box, and then decide that I want to replace text, I press Ctrl+H to switch to the replace mode. This has the side effect of deleting a character as if I pressed backspace.

while using regular expression, or any other method to search for text, when "find next" is selected and a match is found, the search dialog closes. is this part of a feature list? or a bug? this may be a feature request, but it seems more logical that "find next" and "find previous" would retain the open dialog and jump to the next match.
after the dialog closes, pressing ctrl-f to re-open it, replaces your original search query with the highlighted text on the page. is this a wanted feature or should it retain your previous search query?

I don't know why there are two ways for finding/replace. It's annoying for me to press ctr+f and not being able to replace.

Actually, there’s a feature that allows you to press Ctrl+H directly in the dialog and it will switch to replace mode. However this behavior is obsolete and will be replaced by quick find on Ctrl+F, and full find/replace dialog on Ctrl+H. You will be also able to modify this default mapping with the Shortcut Editor.