Hi sir,
I have verry good experience with GUI development, python, Qt and PyQt (or PySide which has better licensing offers by the way). You can have a look at my profile or I can send you sample code if you wish.
According to your requirements, this can be done easilsy with python/Qt module using:
1. Screen size can be retrieved with class QDesktopWidget. Resize events are notified with QEvent (QResizeEvent)
2. QTimer does the job
3. Qt has several classes to read XML (SAX or DOM); for your application, QXmlSimpleReader should be enough. QComboBox implements a drop down menu and with its signals, changes is detected and propagates in the active window
4. QPushButton or QToolButton offers button press events and signals
I set 2 steps here:
1) specifications: have a full list of features to implement. Define environment (os, python version, modules, ...)
2) Coding using open source tools: git, python code, unit tests, ...
Looking forward to hear from you.
Best regards,
Michael