QML editor text previewed on a fullscreen Symbian virtual keyboard disappears when the keyboard window loses focus

Run attached qml example with qmlviewer on Symbian^3 device. Click on the shown TextInput-based text input field. Virtual keyboard opens up. Click options icon button to open input options menu. The preview text shown on the background disappears. The preview text also disappears when other dialogs like "Predictive text activated" note is shown on top of the virtual keyboard. Does not happen on native Symbian editors. Tested on top of sha e46c44f9538dbe5b44ce61d3a42403cfa471ae8b.

See attached no_preview_text.jpg screenshot.