Opening a file with many sequence

There are several issues:

Problem1: UGENE hangs on opening such file when there is not enough memory. For example, I attempt to open "lymph_aln.fastq" when a virtual machine with 2Gb is running on the computer, and UGENE hangs. The same file can be opened when the virtual machine is not running. This issue may be connected with UGENE-1697.

Problem2: If a file contains too many sequences, there is no need to show an option to open the document "as separate sequences in sequence viewer", as it doesn't make sense and may work erroneously.

Problem3: When the file is opened and there is enough memory, UGENE still can hangs for a while if I click on the "Project", "Tasks" or "Log" buttons.

Problem4: When the file is opened, the progress of the "Loading document" task goes up to 100% and holds on this value for some time. UGENE hangs again at that time.