And of course, I checked network before, everything is ok...
Just in case it can't be solved soon, is it possible to revert to 6.2.5 without errors ?

Hi !
I just updated from 6.2.5 to 6.3, and there is a major issue that make projeqtor unusable :
Each time I try to access an element form (example, when I try to open a risk), I got a technical error.
Nothing in log...

Do you already know this issue ?

first, try and clear browser cache.
If problem persists, ckeck for errors in browser console and in apache error log file.
If none shows error, open network tab in browser dev tools, look for last http request and post here response text.

Here is the browser log :

dojo.js?version=V6.3.0.0170:2 [Deprecation] Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience. For more help, check https://xhr.spec.whatwg.org/.
req.getText @ dojo.js?version=V6.3.0.0170:2
projeqtor.js:76 => 686ms | page='today.php' | destination='centerDiv' (server:622ms, client:64ms)
projeqtor.js:76 => 157ms | page='admin.php' | destination='centerDiv' (server:74ms, client:83ms)
projeqtor.js:76 => 363ms | page='objectMain.php' | destination='centerDiv' (server:130ms, client:233ms)
projeqtor.js:76 Erreur sur loadContent('objectStream.php', 'detailRightDiv', 'listForm', 'undefined').
La destination 'detailRightDiv' n'est pas un 'node' ou pas un 'widget'.
objectDetail.php?destinationWidth=1898&destinationHeight=474&isIE= Failed to load resource: the server responded with a status of 500 (Internal Server Error)
projeqtor.js:886 [1] Erreur sur le retour de xhrPost de loadContent('objectDetail.php?destinationWidth=1898&destinationHeight=474&isIE=', 'detailDiv', 'listForm', 'undefined').
RequestError: Unable to load objectDetail.php?destinationWidth=1898&destinationHeight=474&isIE= status: 500
error @ projeqtor.js:886
dojo.js:2 _4a6message: "Unable to load objectDetail.php?destinationWidth=1898&destinationHeight=474&isIE= status: 500"response: ObjectresponseText: ""status: 500xhr: XMLHttpRequeststack: "Error: Unable to load objectDetail.php?destinationWidth=1898&destinationHeight=474&isIE= status: 500↵ at new _4a6 ( http://projeqtor/projeqtor_test/external/dojo/dojo.js?version=V6.3.0.0170:2:125482)↵ at _3e8._31c [as handleResponse] ( http://projeqtor/projeqtor_test/external/dojo/dojo.js?version=V6.3.0.0170:2:84501)↵ at XMLHttpRequest._329 ( http://projeqtor/projeqtor_test/external/dojo/dojo.js?version=V6.3.0.0170:2:84932 )"__proto__: Error
_3c6 @ dojo.js:2
objectDetail.php?destinationWidth=1898&destinationHeight=474&isIE= Failed to load resource: the server responded with a status of 500 (Internal Server Error)
projeqtor.js:886 [1] Erreur sur le retour de xhrPost de loadContent('objectDetail.php?destinationWidth=1898&destinationHeight=474&isIE=', 'detailDiv', 'listForm', 'undefined').
RequestError: Unable to load objectDetail.php?destinationWidth=1898&destinationHeight=474&isIE= status: 500
error @ projeqtor.js:886
dojo.js:2 _4a6
_3c6 @ dojo.js:2
objectDetail.php?destinationWidth=1898&destinationHeight=474&isIE= Failed to load resource: the server responded with a status of 500 (Internal Server Error)
projeqtor.js:886 [2] Erreur sur le retour de xhrPost de loadContent('objectDetail.php?destinationWidth=1898&destinationHeight=474&isIE=', 'detailDiv', 'listForm', 'undefined').
RequestError: Unable to load objectDetail.php?destinationWidth=1898&destinationHeight=474&isIE= status: 500
error @ projeqtor.js:886
dojo.js:2 _4a6
_3c6 @ dojo.js:2
objectDetail.php?destinationWidth=1898&destinationHeight=474&isIE= Failed to load resource: the server responded with a status of 500 (Internal Server Error)
projeqtor.js:891 Erreur sur le retour de xhrPost de loadContent('objectDetail.php?destinationWidth=1898&destinationHeight=474&isIE=', 'detailDiv', 'listForm', 'undefined').
RequestError: Unable to load objectDetail.php?destinationWidth=1898&destinationHeight=474&isIE= status: 500
error @ projeqtor.js:891
dojo.js:2 _4a6
_3c6 @ dojo.js:2
projeqtor.js:76 Erreur sur loadContent('objectStream.php', 'detailRightDiv', 'listForm', 'undefined').
La destination 'detailRightDiv' n'est pas un 'node' ou pas un 'widget'.
objectDetail.php?destinationWidth=1898&destinationHeight=474&isIE= Failed to load resource: the server responded with a status of 500 (Internal Server Error)
projeqtor.js:886 [2] Erreur sur le retour de xhrPost de loadContent('objectDetail.php?destinationWidth=1898&destinationHeight=474&isIE=', 'detailDiv', 'listForm', 'undefined').
RequestError: Unable to load objectDetail.php?destinationWidth=1898&destinationHeight=474&isIE= status: 500
error @ projeqtor.js:886
dojo.js:2 _4a6
_3c6 @ dojo.js:2
objectDetail.php?destinationWidth=1898&destinationHeight=474&isIE= Failed to load resource: the server responded with a status of 500 (Internal Server Error)
projeqtor.js:891 Erreur sur le retour de xhrPost de loadContent('objectDetail.php?destinationWidth=1898&destinationHeight=474&isIE=', 'detailDiv', 'listForm', 'undefined').
RequestError: Unable to load objectDetail.php?destinationWidth=1898&destinationHeight=474&isIE= status: 500
error @ projeqtor.js:891
dojo.js:2 _4a6
_3c6 @ dojo.js:2

It appears you get some "Error 500".
Please check for errors in projeqtor log file and in apache error log file.
If you are using PHP 5.4 or below, you're probably facing an issue that we've fixed on coming patch V6.3.1