GZDoom Builder multiple line selection woes

One of the most common operations when editing for Doom is (quickly) selecting numerous lines in order to edit their values. It seems to me that GZDoom Builder has a quite serious glitch in this regard, or perhaps I'm overlooking an option that would rectify my woes.

The problem is, GZDB will frequently, and seemingly quite at random, deselect all previously selected lines rather than add another line to the selection set, when I click quickly in succession. This leads to tiresome re-selection, or separating large line cues into smaller multi-operation portions to play it safe.

Is there a way to disable double-clicking outside a lineset to reset line selection? This seems to be the feature causing this woe - a deselection feature already more accurately possible by drag-clicking outside of the selection set.

Additionally, when deselection happens, I'm quite sure the editor has registered the line I want it to add, seeing that its highlit - sometimes with a small square placed along the line.

Anyone else experiencing this? Its particularly prevalent when trying to perform a large task efficiently - a way of working I'd hope the editor would always want to be be set up for.

In case there's no remedy from thread contributors, is there a way to get in touch with the keepers of GZDoom Builder on here, to bring up this issue to them? Anyone know their nick, so I can send them a polite PM? After switching from Doom Builder 2.1 to GZDB this has been my main cause for missing anything about the older editor, which doesn't seem as finicky about this issue (perhaps because it doesn't wait to draw the little previously mentioned square over a selected line).

I normally take my time to select multiple linedefs with my mouse because I also experienced that case with Doom Builder 2 while I click the lines too fast.

In my case, Keep pressing Shift button while I'm selecting multiple lines helped me out.

Tools -> Preferences -> Editing -> Start drawing when Edit pressed over empty space in Classic modes

Easiest way to get in contact with MaxED is to use the ZDoom forum thread for GZDB: http://forum.zdoom.org/viewtopic.php?f=3&t=32392