Immediately 'vanishing' popup might mislead users to assume failure

[fabtagon]

There is a UI glitch when saving an EMFText resource as XMI.

reproduce:

• generate language tooling for language foo with EMFText
• edit file.foo using said tooling
• use "Save as" to save as .xmi (e.g. foo.xmi)

What happens:

• foo language is serialized as xmi
• foo editor tries to show the xmi, realizes that this makes no sense, opens a popup with head "No EMFText Resource" and text "The file 'foo.xmi' of type 'xmi' can not be handled by the foo Editor."

Generally that's what we expect so far, but the popup is actually only visible to the user for a fraction of second - after the popup is drawn, Eclipse main window immediately withdraws the editor pane opened for the .xmi file and by that the main window gets focus attention, causing the popup to get behind the main window and leaves the main window in blocked mode (popup is modal). A user that has missed the popup at all might assume the IDE to have frozen.

Desktop setup: two screens on Ubuntu Unity.