recurring unexpected tab closure in ledger

[Jack]

Using a recently compiled version from master branch, when I reconcile 
my investment accounts, I usually start by marking as cleared all the 
transactions in the investment account.  Then I reconcile the brokerage 
account.  Then, with both still open in the ledger, I select the 
investment account, and then the Investments View.  There, I confirm the 
number of shares of all securities held in that account.  I then switch 
back to the Ledgers View to finish the reconciliation of the Investment 
Account.  Over half the time (this has been happening for at least 
several months) the tab for the Investment Account is gone.  The tab for 
the Brokerage Account is still open.

If nobody has any better hints about where to look, I suppose I can run 
in a debugger with a breakpoint on the code which closed the tab (if I 
can find it.)

Any other suggestions?

Jack