In the Timeline view dragging on the time line is difficult and there is likely to be an accessibility problem here in clicking in the right spot and making the right movements. The "window" is not obvious enough and the contrast of colours between the different colours of the sections and the text used is not enough. People who have vision difficulties (or who are a little bit older) will find it difficult to read the text and distinguish between the sections
Provide an alternative way to change the date for month and year (perhaps arrows on either side of the screen?) Improve the contrast or provide a way to change the colours?