When using Arachnophilia, you must stay aware of the position of your cursor.
New items added to a document are always added at the cursors current position. Thus, it is relatively easy to accidentally destroy some code by inserting something in the wrong place. With the exception of the items on the right-click menu (and items you are Select - Surrounding), always ensure that the cursor is on a new line before using any of my toolbars buttons.
If you do accidentally insert something in the wrong place, it is easy to recover as Arachnophilia supports up to 32 levels of Undo/Redo.
If you are unable to locate your cursor for one reason or another, look at the status bar. It will tell you the line and column number that the cursor is currently at. This status bar indicator is also very handy for tracking down script errors...