All right, here is a very back handed solution but it has passed my 15 starts in a row test, twice ! A version of Lazarus 206 built with QT5 instead of GTk2 !
Here is how, if starting from fresh install, see note below if you already have an install. By the way, this is how I always install Lazarus (apart from the Qt5 thing), you end up with a heap more usable system.
Building a QT5 version of Lazarus1. sudo app Install fpc fpc-source <enter> // 580meg, see below if you already have a compiler installed.
2. sudo app install libqt5pas-dev // ~49meg
3. sudo app install subversion <enter> // ~10meg, for the svn command
4. mkdir -p bin/Lazarus; cd bin/Lazarus <enter>
5. svn checkout
http://svn.freepascal.org/svn/lazarus/tags/lazarus_2_0_6 <enter>
6. cd lazarus_2_0_6 <enter>
7. make bigide LCL_PLATFORM=qt5 <enter>
Notes
* If you already have a fpc installed, perhaps from the sourceforge repo, skip step 1. Indeed, if you already have a binary Lazarus install of any sort, please use your package manager (not rm) to remove it, will avoid a lot of confusion later on. But leave your fpc there, it does not matter which one you use as long as its 3.0.4
* Have a look at the wiki page, Installing Lazarus_on_Linux to see how to make menu entries and pretty icons.
* While your Lazarus IDE is using Qt5 widget set, it still defaults to producing gtk2 applications. And, obviously, can be used to make GTK3 or Qt5 ones if you so set it.
* If you distribute Qt5 binaries, don't forget that they will be dependent on libqt5pas1, just marking that as a dependency is enough, the package managers will pull down the other necessary libraries. That dependancy is worth 49Meg of disk, compare to GTK2.0 at 321Meg. Hmm....
If we find other people can confirm that this fixes their problem, it leaves me wondering if the issue is within Ubuntu's GTK2 kit. Frankly, I don't think they will be willing to put much effort into fixing it if that's the case ! Nasty.
Thank sash on the forum for putting this idea into my head.