Moved initialisation of overview and detail pane tabs into AfterShowForm because selecting detail pane tab in InitForm causes a divide by zero error in IE 10 browser control.
This fixes bug #82 - "Fatal divide by zero exception on start-up" (https://sourceforge.net/p/codesnip/bugs/82/), which is similar to bug #75 - "Floating point error in 4.4.1 (portable)" reported for Windows 8.
