Firefox keeps crashing

Ironically I use Roll20 Virtual Table Top to play a real tabletop campaign of D&D 4e. Basically I have a laptop extending a display to a ceiling mounted projector that projects down on to a whiteboard on a table on which I use a mix of miniatures and Roll20 tokens on the Roll20 maps (image attached for context :).  I have two roll20 sessions open, two firefox windows - one on my laptop screen - as the GM view (50%), and then the projected screen (60%) which I, as GM have joined as a player. There is no voice/video or 3d dice. There are no other players joined. I dont use Google Hangouts - just plain firefox and Roll 20. I am getting a number of problems (and have done since I started using Roll20 for the last 2 months), : i) After about an hour or so firefox just crashes, and then every 15 minutes or so, with a "this is embarassing" window (yeah it is). Its using about 800Mb-1Gb memory. I am running DnD4eCM and OneNote on the latop screen as well and that is working ok. I have limited the number of other programs I have running. ii) The map on the player view keeps disapearing (black backround, but with the VTT toolbar, though firefox is still running), if I am lucky I can stilll interact with the GM session and move the players between maps (to refresh it) usually though the GM session is locked up as per my point below. iii) The interaction with the VTT stops, I cant select or move tokens (the correct layer is active), I can't pan or ping or swich between tabs in the chat/handout/jukebox panel. Sometimes after 2or 3 minutes I can interact, usually though firefox crashes or I have to kill it. I am using firefox 18.0.2 on Windows 7 Ultimate, 32 Bit, Flash 11.5.502, Java SE6 Update 33 (is the Java relevant ?) on a DELL laptop with 4Gb RAM. Should I switch to Chrome? Does running 2 sessions on same PC, GM and same user and player cause issues ? Is the memory usage normal ? What addons/extensions/versions does Roll 20 rely on - so that I can disable anything else that may be running ( e.g. is it Flash and Java or ... ? ) Any advice appreciated. Obsidian.

Try just switching to google chrome it works awesome, you just have to  refresh once in a while after alot of copy paste. perhaps using two diffident browsers maybe.

With the two firefox sessions running - but with no interaction - I monitored the memory usage of firefox - it would increase from 800 Mb to 1 Gb over 1 minure, drop back to 820 - then 1.1 Gb, then 890 - to 1.2 Gb until gradually (over half an hour maybe?) it bounced from about 900 up to 1.3Gb at which point the map would go black (and sometimes clicking on the window might refresh map, or a forced refresh would refresh map or or firefox would crash. To simplify the test - I just had one firefox window open, a single connection as GM. With dynamic lighting enabled on a map ( with tokens ) and 9 sources of light, again no interaction - the memory usage started bouncing from 360M - 560M over a minute (at a rate of 2-5Mb a second), then drop to 370-565, 375-570 etc. I didnt leave the test long enough to see if it crashed but presumably over time the memory usage would get to the point where it would crash (its just magnified when two sessions are running) I then disabled dynamic lighting for the page, with tokens - and the memory usage was approx 400M - but increased at about 20-80K per minute (not dropping back) - I didnt leave this run for long just observed that it was increasing slowly. I then chose a page with no tokens, no lighting, just a jpg image as a background. No interaction - this still increasedmemory usage @ a rate of 20-80K per minute. I closed down the VTT completely - and just have firefox open sitting on the google homepage - at about 122 Mb used. It is bouncing between 123-126k and dropping back at a rate of about 20k per minute. Its late here in the UK now, so I will carry on investigating if any addons are producing the residual 20K increase tomorrow.

I have disabled all add-ons in Firefox. Memory usage (with two screens running and with dynamic lighting enabled, tokens on a page) so far (after 30 minutes) seems stable at 470 Mb. Will monitor during the day and post an update. Hopefully it looks like it's a Firefox add-on issue, and as Roll20 doesnt need add-ons the issue may be avoidable.

Ok, over 6 hours the memory usage bounced up and down between 470Mb to 520 Mb in Firefox (total for two windows, one player and one GM) with all firefox addons disabled, dynamic lighting enabled (multiple sources) with the result that I had no maps disappearing/redrawing and no firefox crashes - hurrah. Of course I am assuming that the memory usage will depend on the map size, number of tokens etc, but even on my largest and busiest map the usage was 620-670Mb (two windows) This is now usable for me :) So my advice would be if you are using firefox, for your Roll20 sessions disable your firefox addons and this seems to reduce/eliminate the map redraw and firefox crashes. Hope this helps anybody else who has had the same issues.

An alternative is switching to the Aurora release stream for Firefox (it's the 20.x releases at this point) - they seem to have finally smashed some of the memory-usage issues in it.