Rebase dialog does not change "Start (FastFwd)" button during rebase process

What steps will reproduce the problem?

1. When rebasing, Rebase dialog is opened. (Can be trigerred from pull menu when "Launch Rebase After Fetch" is checked.)
2. Press "Start (FastFwd)" button.
3. Rebase process starts. The button label still shows "Start (FastFwd)".
4. After rebase is finished completely, button label is changed to "Done".

What is the expected output? What do you see instead?

Step 3: After pressing "Start (FastFwd)" button, I suggest to change its text ("Rebase in progress..." or similar, maybe shorter: "Working...") to differentiate it from not yet pressed "Start (FastFwd)" button. (Maybe also during the rebase process, button might be disabled because currently button is--or at least seams to be--active all the time.)

What version of TortoiseGit and Git are you using? On what operating system?

Windows 10, TortoiseGit 2.4.0.2, git version 2.10.1.windows.1