When the user has a window smaller then the given fixed height, half of the UI is unreachable. At first sight, there is some fixed height + absolute positioning which is not really needed. Removing them and adjusting the related css properties should do the job.
Looking at it better, remove the fixed height is not an easy thing... we go for fixing the resizing by keeping the same layout - two column based with fixed height.
When the user has a window smaller then the given fixed height, half of the UI is unreachable. At first sight, there is some fixed height + absolute positioning which is not really needed. Removing them and adjusting the related css properties should do the job.