Visual Basic on Remko's Blog

Change Tab Order in an Executable

Wed, 02 Jan 2013 15:03:14 +0000

An application called Cardiology PACS was recently packaged for a Citrix XenApp environment. The functional tester reported a strange problem at the logon screen: after entering the username it was not possible to go to the password field with the TAB key.

This was a strange observation since I cannot imagine XenApp interfering with tab stops. So what was going on?

In the old situation the user was starting the application on his local pc. The application remembered the last username and pre-filled this, therefore the cursor was already in the Password field. The user simply entered his password and hit the Enter key:

On XenApp the Username field is not pre-filled because the last username is kept globally per machine. Therefore the user has to enter both the username and the password:

I tested the Tab key behavior in both situations and as I expected it didn’t work in both situations. This happens because the Tab Order has been messed up by the programmer (if you press Tab 9 times you do end up in the Username field).

Because this is something that would annoy me if I were the user I decided to fix it.

Modify VB Executable to force Taskbar Button

Sat, 04 Aug 2012 11:07:18 +0000

I had to troubleshoot an application that was published with Citrix XenApp. The problem with this application was that it didn't have an button/icon in the taskbar and the window would sometimes disappear.

I noticed that this (cr)application was written in Visual Basic, so I decided to run it through a decompilation tool.

The decompiler was able to list the forms used in the Application:

Error 372 in Thinapped Visual Basic Application

Tue, 03 Jan 2012 22:34:29 +0000

Today I was troubleshooting a Thinapped Visual Basic Application. The application halts with a Run-time error '372' when trying to run a report:

Microsoft KB article kb942870 hints to an ActiveX component that is registered into HKCU instead of HKLM.

A trace with the ThinApp Log Monitor reveals that the application is looking for an ActiveX component under HKCU: