We received a few reports where the editor was 'overwriting' the code when typed. It was related to this option being changed accidentally.
The top right bar, you will find a 'T' font icon. When it is blue (not highlighted) you are in insert mode. So if I have the following line:
$afunction();
In insert mode, if I put the cursor between the 'a' and 'f' in function and type ' = ' I will get:
$a = function();
Overwrite mode, which will be indicated by the 'T' icon highlighted and a single line through it, will type OVER existing code. This mode is useful at times and is a preference. Doing the same thing to the above code (for example purposes) would become:
$a = ction();
Because the editor was set to 'overwrite' existing code.
Hope this helps!
Checking the overwrite mode in the editor tab on the left slide menu will do the same. :-)