iFix 5.1 - Odd UserForm position behaviour

First, a thanks goes to forum contributors. A number of your posts here have helped me create an almost working HMI feature.

My project is pretty basic: Spawn a custom UserForm at my cursor when I click a DataLink object on a picture. Thanks to this forum and a few others I've been able to make the custom form spawn precisely where I want it. There is only one catch: It only works if I execute a MsgBox function call prior to Me.Show.

In my testing I observe the same behaviour even when I manually set the Top and Left position parameters of the form (during runtime) using either Me.Move or Me.Top, Me.Left. Additionally, the form's StartUpPosition parameter presets also consistently spawns the form in the center of the right-hand screen on a dual monitor system regardless which mode you set it to. Even when using the position presets the form only works properly when you call MsgBox before Me.Show

Has anyone encountered this or have a an idea what is causing it?

Thanks,
LK