When creating a title clip and editing it's duration via 'right-click -> edit duration' (or simply by making it longer with the mouse-cursor) that change is not saved correctly. It then causes problems when moving the title clip or simply restarting the project.

STEPS TO REPRODUCE:
1. create a title with the default duration of 5 seconds
2. click ok to apply
3. drag that clip onto a track
4. change the duration to 10 seconds, either via 'right-click -> edit duration' (or by using the mouse-cursor)
5. drag the clip onto another track.
alternatively to 5: save the project, close Kdenlive, restart it and open the project again

OBSERVED RESULT:
As soon as the title clip has been moved to another track, it's length reverts back to whatever was entered in the Title Clip Editor (eg. the default value of 5Sec). 
The same goes, when you don't move the title clip to another track but save, exit out of kdenlive and the reload the project. The clips length is reverted back to it's original length. 
This, of course, then means that every clip on the save track is moved aswell!

EXPECTED RESULT:
Changing the duration via 'right-click -> edit duration' (or by using the mouse-cursor) should be applied successfully, no matter if the clip is moved to another track afterwards or if kdenlive and the projet is restarted.


SOFTWARE/OS VERSIONS
Linux:  Kernel: 5.4.0-90-generic x86_64 bits: 64 compiler: gcc v: 9.3.0 Desktop: Cinnamon 5.0.7 
wm: muffin dm: LightDM Distro: Linux Mint 20.2 Uma base: Ubuntu 20.04 focal 

Machine:   Type: Desktop Mobo: ASUSTeK model: PRIME X470-PRO v: Rev X.0x serial: <filter> 
           UEFI [Legacy]: American Megatrends v: 5603 date: 07/28/2020 
CPU:       Topology: 8-Core model: AMD Ryzen 7 2700X bits: 64 type: MT MCP arch: Zen+ rev: 2 
           L2 cache: 4096 KiB 
           flags: avx avx2 lm nx pae sse sse2 sse3 sse4_1 sse4_2 sse4a ssse3 svm bogomips: 118163 
           Speed: 1889 MHz min/max: 2200/3700 MHz Core speeds (MHz): 1: 1884 2: 1886 3: 2055 
           4: 2067 5: 2130 6: 2113 7: 2193 8: 2189 9: 2045 10: 1889 11: 2009 12: 2191 13: 2190 
           14: 2188 15: 2191 16: 1907 
Graphics:  Device-1: NVIDIA GP106 [GeForce GTX 1060 6GB] driver: nvidia v: 470.82.00 
           bus ID: 08:00.0 chip ID: 10de:1c03 
           Display: x11 server: X.Org 1.20.11 driver: nvidia 
           resolution: 3840x2160~60Hz, 3840x2160~60Hz 
           OpenGL: renderer: NVIDIA GeForce GTX 1060 6GB/PCIe/SSE2 v: 4.6.0 NVIDIA 470.82.00 
           direct render: Yes 
Audio:     Device-1: NVIDIA GP106 High Definition Audio driver: snd_hda_intel v: kernel 
           bus ID: 08:00.1 chip ID: 10de:10f1 
           Device-2: AMD Family 17h HD Audio vendor: ASUSTeK driver: snd_hda_intel v: kernel 
           bus ID: 0a:00.3 chip ID: 1022:1457 
           Sound Server: ALSA v: k5.4.0-90-generic 
Network:   Device-1: Intel I211 Gigabit Network vendor: ASUSTeK driver: igb v: 5.6.0-k port: e000 
           bus ID: 06:00.0 chip ID: 8086:1539 
           IF: enp6s0 state: up speed: 1000 Mbps duplex: full mac: <filter> 
           IF-ID-1: virbr0 state: down mac: <filter> 
           IF-ID-2: virbr0-nic state: down mac: <filter> 
Drives:    Local Storage: total: 13.42 TiB used: 3.35 TiB (25.0%) 
           ID-1: /dev/sda vendor: Samsung model: SSD 850 EVO 250GB size: 232.89 GiB 
           speed: 6.0 Gb/s serial: <filter> 
           ID-2: /dev/sdb vendor: Crucial model: CT500MX500SSD1 size: 465.76 GiB speed: 6.0 Gb/s 
           serial: <filter> 
           ID-3: /dev/sdg vendor: Seagate model: ST14000VE0008-2KV101 size: 12.73 TiB 
           speed: 6.0 Gb/s serial: <filter>