After ofSystemLoadDialog drawing is suspended

This is with 0.9.0

An ofxDatGuiButtonEvent triggers a system open file dialog:

void ofApp::onOfxDatGuiButtonEvent(ofxDatGuiButtonEvent e) {
    if (e.target == controls.loadButton) {
        ofFileDialogResult openFileResult = ofSystemLoadDialog("Select a CSV dataset file");
        if (openFileResult.bSuccess) {
            // this draws to an FBO which is drawn in main draw()
            dataSource.load(openFileResult.getPath());
        }
    }
}

After that drawing is not updated. Not the FBO, the overlaid real time stuff in my draw() loop of the datGui sidebar.

If I background the app (click on a different OS window) and go back, then drawing updates return.

Is it a bug ? Is there a trick ?