From time to time there is a bug when you scroll down trough larger html files (only some kb). The scrollbar arrives at the end, but that doesnā€™t correspond with the file. So you canā€™t arrive (or scroll) to the rest of the file. Reopening helps from time to time, but not always. Scrolling with the keyboard (arrow keys) results in the same, scrollbar is at the end, file isnā€™t. Sometimes it helps using screen down key, but very often this results in showing only empty lines (line numbers are there on the left) at first. Then, after selecting ā€blankā€¯ text, the text appears.
Another thing (I would not call it bug) is, when you select text with the mouse, press shift and click further down in the text to increase the selection. In Word or other editors, this works. In HTMLPad, this starts a new selection, beginning from the character where the first selection ends, going to the click point. On the other side, when you select some text from button up and increase the selection with some text further down, this works (the same with top down).