I have a module, the size is over 30KB, with 1400 lines of code. Only this big module has this issue............ The basic4ppc version is 6.90. When I edit source code in the Device IDE, the new space will replace character at the cursor INSTEAD OF add new space. For example, the following code: Dim tStr As String <=== 1 space between "Dim" and "tStr" If the cursor is just BEFORE the t of "tStr" and adding a space, it should be: Dim tStr As String <=== should be 2 space between "Dim" and "tStr" But, the Device IDE causes my code as below: Dim Str As String <=== erased the t Adding space to this module is OverWrite mode now, NOT Insert mode. Very Very inconvenience. If this bug is NOT caused by big module, what will cause this bug?