Once the project monitor window has been "popped out" of the main, grid-based user interface into a separate "window", that window can not be made bigger, only smaller. i.e., place the mouse cursor at one of its corners until the resize cursor appears, and then try dragging it bigger. It won't get bigger, only smaller, until it's too small to use.
Please try with the current Kdenlive AppImage version 19.08.3b to see if there are any packaging issues https://files.kde.org/kdenlive/release/ If the problem/issue doesn't occur when using the AppImage, then it's your configuration or packaging.
Dear Bug Submitter, This bug has been in NEEDSINFO status with no change for at least 15 days. Please provide the requested information as soon as possible and set the bug status as REPORTED. Due to regular bug tracker maintenance, if the bug is still in NEEDSINFO status with no change in 30 days the bug will be closed as RESOLVED > WORKSFORME due to lack of needed information. For more information about our bug triaging procedures please read the wiki located here: https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging If you have already provided the requested information, please mark the bug as REPORTED so that the KDE team knows that the bug is ready to be confirmed. Thank you for helping us make KDE software even better for everyone!
This bug has been in NEEDSINFO status with no change for at least 30 days. The bug is now closed as RESOLVED > WORKSFORME due to lack of needed information. For more information about our bug triaging procedures please read the wiki located here: https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging Thank you for helping us make KDE software even better for everyone!